Science.gov

Sample records for estuary engineering feasibility

  1. Deschutes estuary feasibility study: hydrodynamics and sediment transport modeling

    USGS Publications Warehouse

    George, Douglas A.; Gelfenbaum, Guy; Lesser, Giles; Stevens, Andrew W.

    2006-01-01

    - Provide the completed study to the CLAMP Steering Committee so that a recommendation about a long-term aquatic environment of the basin can be made. The hydrodynamic and sediment transport modeling task developed a number of different model simulations using a process-based morphological model, Delft3D, to help address these goals. Modeling results provide a qualitative assessment of estuarine behavior both prior to dam construction and after various post-dam removal scenarios. Quantitative data from the model is used in the companion biological assessment and engineering design components of the overall study. Overall, the modeling study found that after dam removal, tidal and estuarine processes are immediately restored, with marine water from Budd Inlet carried into North and Middle Basin on each rising tide and mud flats being exposed with each falling tide. Within the first year after dam removal, tidal processes, along with the occasional river floods, act to modify the estuary bed by redistributing sediment through erosion and deposition. The morphological response of the bed is rapid during the first couple of years, then slows as a dynamic equilibrium is reached within three to five years. By ten years after dam removal, the overall hydrodynamic and morphologic behavior of the estuary is similar to the pre-dam estuary, with the exception of South Basin, which has been permanently modified by human activities. In addition to a qualitative assessment of estuarine behavior, process-based modeling provides the ability address specific questions to help to inform decision-making. Considering that predicting future conditions of a complex estuarine environment is wrought with uncertainties, quantitative results in this report are often expressed in terms of ranges of possible outcomes.

  2. Renewable Energy Park - Preliminary Feasibility & Engineering Report

    SciTech Connect

    Ariwite, Roderick

    2015-07-31

    This "Renewable Energy Park - Preliminary Feasibility & Engineering Report" seeks to provide an overall assessment and review of renewable energy development opportunities on the Fallon Indian Reservation and Colony Lands.

  3. Artemis: Results of the engineering feasibility study

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Information is given in viewgraph form for the Engineering Feasibility Study of the Artemis Project, a plan to establish a permanent base on the Moon. Topics covered include the Common Lunar Lander (CLL), lunar lander engineering study results, lunar lander trajectory analysis, lunar lander conceptual design and mass properties, the lunar lander communication subsystem design, and product assurance.

  4. Feasibility study for convertible engine torque converter

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The feasibility study has shown that a dump/fill type torque converter has excellent potential for the convertible fan/shaft engine. The torque converter space requirement permits internal housing within the normal flow path of a turbofan engine at acceptable engine weight. The unit permits operating the engine in the turboshaft mode by decoupling the fan. To convert to turbofan mode, the torque converter overdrive capability bring the fan speed up to the power turbine speed to permit engagement of a mechanical lockup device when the shaft speed are synchronized. The conversion to turbofan mode can be made without drop of power turbine speed in less than 10 sec. Total thrust delivered to the aircraft by the proprotor, fan, and engine during tansient can be controlled to prevent loss of air speed or altitude. Heat rejection to the oil is low, and additional oil cooling capacity is not required. The turbofan engine aerodynamic design is basically uncompromised by convertibility and allows proper fan design for quiet and efficient cruise operation. Although the results of the feasibility study are exceedingly encouraging, it must be noted that they are based on extrapolation of limited existing data on torque converters. A component test program with three trial torque converter designs and concurrent computer modeling for fluid flow, stress, and dynamics, updated with test results from each unit, is recommended.

  5. Restoration of Hydrodynamic and Hydrologic Processes in the Chinook River Estuary, Washington – Feasibility Assessment

    SciTech Connect

    Khangaonkar, Tarang P.; Breithaupt, Stephen A.; Kristanovich, Felix C.

    2006-08-03

    A hydrodynamic and hydrologic modeling analysis was conducted to evaluate the feasibility of restoring natural estuarine functions and tidal marine wetlands habitat in the Chinook River estuary, located near the mouth of the Columbia River in Washington. The reduction in salmonid populations is attributable primarily to the construction of a Highway 101 overpass across the mouth of the Chinook River in the early 1920s with a tide gate under the overpass. This construction, which was designed to eliminate tidal action in the estuary, has impeded the upstream passage of salmonids. The goal of the Chinook River Restoration Project is to restore tidal functions through the estuary, by removing the tide gate at the mouth of the river, filling drainage ditches, restoring tidal swales, and reforesting riparian areas. The hydrologic model (HEC-HMS) was used to compute Chinook River and tributary inflows for use as input to the hydrodynamic model at the project area boundary. The hydrodynamic model (RMA-10) was used to generate information on water levels, velocities, salinity, and inundation during both normal tides and 100-year storm conditions under existing conditions and under the restoration alternatives. The RMA-10 model was extended well upstream of the normal tidal flats into the watershed domain to correctly simulate flooding and drainage with tidal effects included, using the wetting and drying schemes. The major conclusion of the hydrologic and hydrodynamic modeling study was that restoration of the tidal functions in the Chinook River estuary would be feasible through opening or removal of the tide gate. Implementation of the preferred alternative (removal of the tide gate, restoration of the channel under Hwy 101 to a 200-foot width, and construction of an internal levee inside the project area) would provide the required restorations benefits (inundation, habitat, velocities, and salinity penetration, etc.) and meet flood protection requirements. The alternative design included design of storage such that relatively little difference in the drainage or inundation upstream of Chinook River Valley Road would occur as a result of the proposed restoration activities.

  6. Restoration of Hydrodynamic and Hydrologic Processes in the Chinook River Estuary, Washington – Feasibility Assessment

    SciTech Connect

    Khangaonkar, Tarang P.; Breithaupt, Stephen A.; Kristanovich, Felix C.

    2006-01-01

    A hydrodynamic and hydrologic modeling analysis was conducted to evaluate the feasibility of restoring natural estuarine functions and tidal marine wetlands habitat in the Chinook River estuary, located near the mouth of the Columbia River in Washington. The reduction in salmonid populations is attributable primarily to the construction of a Highway 101 overpass across the mouth of the Chinook River in the early 1920s with a tide gate under the overpass. This construction, which was designed to eliminate tidal action in the estuary, has impeded the upstream passage of salmonids. The goal of the Chinook River Restoration Project is to restore tidal functions through the estuary, by removing the tide gate at the mouth of the river, filling drainage ditches, restoring tidal swales, and reforesting riparian areas. The hydrologic model (HEC-HMS) was used to compute Chinook River and tributary inflows for use as input to the hydrodynamic model at the project area boundary. The hydrodynamic model (RMA-10) was used to generate information on water levels, velocities, salinity, and inundation during both normal tides and 100-year storm conditions under existing conditions and under the restoration alternatives. The RMA-10 model was extended well upstream of the normal tidal flats into the watershed domain to correctly simulate flooding anddrainage with tidal effects included, using the wetting and drying schemes. The major conclusion of the hydrologic and hydrodynamic modeling study was that restoration of the tidal functions in the Chinook River estuary would be feasible through opening or removal of the tide gate. Implementation of the preferred alternative (removal of the tide gate, restoration of the channel under Hwy 101 to a 200-foot width, and construction of an internal levee inside the project area) would provide the required restorations benefits (inundation, habitat, velocities, and salinity penetration, etc.) and meet flood protection requirements. The alternative design included design of storage such that relatively little difference in the drainage or inundation upstream of Chinook River Valley Road would occur as a result of the proposed restoration activities.

  7. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon

    EPA Science Inventory

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  8. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon - April 2009

    EPA Science Inventory

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  9. Laser engines operating by resonance absorption. [thermodynamic feasibility study

    NASA Technical Reports Server (NTRS)

    Garbuny, M.; Pechersky, M. J.

    1976-01-01

    Basic tutorial article on the thermodynamic feasibility of laser engines at the present state of the art. Three main options are considered: (1) laser power applied externally to a heat reservoir (boiler approach); (2) internal heating of working fluid by resonance absorption; and (3) direct conversion of selective excitation into work. Only (2) is considered practically feasible at present. Basic concepts and variants, efficiency relations, upper temperature limits of laser engines, selection of absorbing gases, engine walls, bleaching, thermodynamic cycles of optimized laser engines, laser-powered turbines, laser heat pumps are discussed. Photon engines and laser dissociation engines are also considered.

  10. Magma energy: engineering feasibility of energy extraction from magma bodies

    SciTech Connect

    Traeger, R.K.

    1983-12-01

    A research program was carried out from 1975 to 1982 to evaluate the scientific feasibility of extracting energy from magma, i.e., to determine if there were any fundamental scientific roadblocks to tapping molten magma bodies at depth. The next stage of the program is to evaluate the engineering feasibility of extracting energy from magma bodies and to provide insight into system economics. This report summarizes the plans, schedules and estimated costs for the engineering feasibility study. Tentative tasks and schedules are presented for discussion and critique. A bibliography of past publications on magma energy is appended for further reference. 69 references.

  11. Managing Nutrients in two New England Estuaries: The Feasibility of Using Stable Isotopes to Monitor Nitrate Sources

    NASA Astrophysics Data System (ADS)

    Barnes, R. T.; Benoit, G.; Anisfeld, S.

    2004-12-01

    Nitrogen is the limiting nutrient in many estuaries, and the rising availability of nitrogen has led to increased eutrophication in many coastal ecosystems. In order to reduce nitrogen loading to coastal waters it is necessary to know the relative importance of the various sources, both point and non-point. Recent studies have shown that sources of nitrate, the most bioavailable form of nitrogen, can be differentiated based on their isotopic signature using a dual stable isotope approach (\\delta15N and \\delta18O). Currently, the range of isotopic values in the literature for nitrate sources (sewage, atmospheric deposition, microbial nitrification, fertilizer and animal waste) across various systems is too large to clearly differentiate between sources. In this study, I will use a stratified sampling plan to assess the feasibility of using this stable isotope approach to determine the relative importance of various nitrogen inputs in a limited geographic region. I will examine how these isotope signatures vary spatially across different watersheds and how much sampling (spatially and temporally) is needed to accurately assess the delivery of nitrogen to a given estuary. In particular, four estuarine catchments within two different New England estuaries will be sampled at three different scales. At the smallest scale, first and second order forested, agricultural, and urban catchments will be sampled to identify source signatures of these landscapes. Tributaries, mostly third order streams, will be sampled to gain additional information about the relationship between land cover and isotopic signatures. At the largest scale, longitudinal sampling will be done along the main stems to assess the relative contributions of different tributaries and to provide further information regarding nitrogen cycling within these systems. Various chemical indicators of nitrogen loading will also be measured to assess their use in conjunction with the stable isotopes. This suite of measurements will help determine the best strategy (in terms of both time and cost) for detecting watershed nitrogen loading to estuaries.

  12. Recruitment dynamics of two ecosystem engineers could drive shellfish populations in U.S. west coast estuaries

    EPA Science Inventory

    Two species of burrowing shrimp, Neotrypaea californiensis and Upogebia pugettensis are important members of intertidal mudflat communities in US West coast estuaries. Both species act as ecosystem engineers and influence the presence of other structured habitats and suspension ...

  13. Disturbance facilitates the coexistence of antagonistic ecosystem engineers in California estuaries.

    PubMed

    Castorani, Max C N; Hovel, Kevin A; Williams, Susan L; Baskett, Marissa L

    2014-08-01

    Ecological theory predicts that interactions between antagonistic ecosystem engineers can lead to local competitive exclusion, but disturbance can facilitate broader coexistence. However, few empirical studies have tested the potential for disturbance to mediate competition between engineers. We examined the capacity for disturbance and habitat modification to explain the disjunct distributions of two benthic ecosystem engineers, eelgrass Zostera marina and the burrowing ghost shrimp Neotrypaea californiensis, in two California estuaries. Sediment sampling in eelgrass and ghost shrimp patches revealed that ghost shrimp change benthic biogeochemistry over small scales (centimeters) but not patch scales (meters to tens of meters), suggesting a limited capacity for sediment modification to explain species distributions. To determine the relative competitive abilities of engineers, we conducted reciprocal transplantations of ghost shrimp and eelgrass. Local ghost shrimp densities declined rapidly following the addition of eelgrass, and transplanted eelgrass expanded laterally into the surrounding ghost shrimp-dominated areas. When transplanted into eelgrass patches, ghost shrimp failed to persist. Ghost shrimp were also displaced from plots with structural mimics of eelgrass rhizomes and roots, suggesting that autogenic habitat modification by eelgrass is an important mechanism determining ghost shrimp distributions. However, ghost shrimp were able to rapidly colonize experimental disturbances to eelgrass patch edges, which are common in shallow estuaries. We conclude that coexistence in this system is maintained by spatiotemporally asynchronous disturbances and a competition-colonization trade-off: eelgrass is a competitively superior ecosystem engineer, but benthic disturbances permit the coexistence of ghost shrimp at the landscape scale by modulating the availability of space. PMID:25230478

  14. 75 FR 77798 - Interpretation of OSHA's Provisions for Feasible Administrative or Engineering Controls of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-14

    .... Authority: 29 U.S.C. 655; 29 CFR 1910.95(b)(1) & 1926.52(b); Secretary of Labor's Order 4-2010, 75 FR 55355... for Feasible Administrative or Engineering Controls of Occupational Noise AGENCY: Occupational Safety... Interpretation of OSHA's Provisions for Feasible Administrative or Engineering Controls of Occupational...

  15. MORE THAN JUST BAIT: BURROWING SHRIMP AS ECOSYSTEM ENGINEERS IN OREGON ESTUARIES - SEPTEMBER 2006

    EPA Science Inventory

    Burrowing shrimp may be most widely known as excellent fishing bait, but they also play important roles in estuaries of the Pacific Northwest. These shrimps strongly affect carbon and nutrient cycling, phytoplankton abundance, food web structure and dynamics, sediment stability,...

  16. Feasibility of magnetic bearings for advanced gas turbine engines

    NASA Astrophysics Data System (ADS)

    Hibner, David; Rosado, Lewis

    1992-05-01

    The application of active magnetic bearings to advanced gas turbine engines will provide a product with major improvements compared to current oil lubricated bearing designs. A rethinking of the engine rotating and static structure design is necessary and will provide the designer with significantly more freedom to meet the demanding goals of improved performance, increased durability, higher reliability, and increased thrust to weight ratio via engine weight reduction. The product specific technology necessary for this high speed, high temperature, dynamically complex application has been defined. The resulting benefits from this approach to aircraft engine rotor support and the complementary engine changes and improvements have been assessed.

  17. Exoskeletal Engine Concept: Feasibility Studies for Medium and Small Thrust Engines

    NASA Technical Reports Server (NTRS)

    Halliwell, Ian

    2001-01-01

    The exoskeletal engine concept is one in which the shafts and disks are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Omission of the shafts and disks leads to an open channel at the engine centerline. This has immense potential for reduced jet noise and for the accomodation of an alternative form of thruster for use in a combined cycle. The use of ceramic composite materials has the potential for significantly reduced weight as well as higher working temperatures without cooling air. The exoskeletal configuration is also a natural stepping-stone to complete counter-rotating turbomachinery. Ultimately this will lead to reductions in weight, length, parts count and improved efficiency. The feasibility studies are in three parts. Part I-Systems and Component Requirements addressed the mechanical aspects of components from a functionality perspective. This effort laid the groundwork for preliminary design studies. Although important, it is not felt to be particularly original, and has therefore not been included in the current overview. Part 2-Preliminary Design Studies turned to some of the cycle and performance issues inherent in an exoskeletal configuration and some initial attempts at preliminary design of turbomachinery were described. Twin-spoon and single-spool 25.800-lbf-thrust turbofans were used as reference vehicles in a mid-size commercial subsonic category in addition to a single-spool 5,000-lbf-thrust turbofan that represented a general aviation application. The exoskeletal engine, with its open centerline, has tremendous potential for noise suppression and some preliminary analysis was done which began to quantify the benefits. Part 3-Additional Preliminary Design Studies revisited the design of single-spool 25,800-lbf-thrust turbofan configurations, but in addition to the original FPR = 1.6 and BPR = 5.1 reference engine, two additional configurations used FPR = 2.4 and BPR = 3.0 and FPR = 3.2 and BPR = 2.0 were investigated. The single-spool 5,000-lbf-thrust turbofan was refined and the small engine study was extended to include a 2,000-lbf-thrust turbojet. More attention was paid to optimizing the turbomachinery. Turbine cooling flows were eliminated, in keeping with the use of uncooled CMC material in exoskeletal engines. The turbine performance parameters moved much closer to the nominal target values, demonstrating the great benefits to the cycle of uncooled turbines.

  18. Exoskeletal Engine Concept: Feasibility Studies for Medium and Small Thrust Engines

    NASA Technical Reports Server (NTRS)

    Halliwell, Ian

    2001-01-01

    The exoskeletal engine concept is one in which the shafts and disks are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Omission of the shafts and disks leads to an open channel at the engine centerline. This has immense potential for reduced jet noise and for the accommodation of an alternative form of thruster for use in a combined cycle. The use of ceramic composite materials has the potential for significantly reduced weight as well as higher working temperatures without cooling air. The exoskeletal configuration is also a natural stepping-stone to complete counter-rotating turbomachinery. Ultimately this will lead to reductions in weight, length, parts count and improved efficiency. The feasibility studies are in three parts. Part 1: Systems and Component Requirements addressed the mechanical aspects of components from a functionality perspective. This effort laid the groundwork for preliminary design studies. Although important, it is not felt to be particularly original, and has therefore not been included in the current overview. Part 2: Preliminary Design Studies turned to some of the cycle and performance issues inherent in an exoskeletal configuration and some initial attempts at preliminary design of turbomachinery were described. Twin-spoon and single-spool 25,800-lbf-thrust turbofans were used as reference vehicles in a mid-size commercial subsonic category in addition to a single-spool 5,000-lbf-thrust turbofan that represented a general aviation application. The exoskeletal engine, with its open centerline, has tremendous potential for noise suppression and some preliminary analysis was done which began to quantify the benefits. Part 3: Additional Preliminary Design Studies revisited the design of single-spool 25,800-lbf-thrust turbofan configurations, but in addition to the original FPR = 1.6 and BPR = 5.1 reference engine. two additional configurations used FPR = 2.4 and BPR = 3.0 and FPR = 3.2 and BPR = 2.0 were investigated. The single-spool 5.000-lbf-thrust turbofan was refined and the small engine study was extended to include a 2,000-lbf-thrust turbojet. More attention was paid to optimizing the turbomachinery. Turbine cooling flows were eliminated, in keeping with the use of uncooled CMC materials in exoskeletal engines. The turbine performance parameters moved much closer to the nominal target values, demonstrating the great benefits to the cycle of uncooled turbines.

  19. Session 6: Magma Energy: Engineering Feasibility of Energy Extraction from Magma Bodies

    SciTech Connect

    Traeger, R.K.

    1983-12-01

    Extensive quantities of high-quality energy are estimated to be available from molten magma bodies existing within 10 Km of the US continent's surface. A five-year study sponsored by DOE/BES demonstrated that extraction of energy from these melts was scientifically feasible. The next stage of assessment is to evaluate the engineering feasibility of energy extraction and provide a preliminary economic evaluation. Should the second step demonstrate engineering feasibility, the third step would include detailed economic, market and commercialization endeavors. Evaluation of the engineering feasibility will be initiated in FY 84 in a program supported by DOE/GHTD and managed by Dave Allen. The project will be managed by Sandia Labs in James Kelsey's Geothermal Technology Development Division. The project will continue to draw on expertise throughout the country, especially the scientific base established in the previous BES Magma Energy Program.

  20. Engineering feasibility of in-situ subsurface isolation barriers

    SciTech Connect

    Carter, E.E.

    2007-07-01

    In the remediation of radioactive waste disposal sites there are occasional situations where it is not feasible to remove the waste or contaminated soil and a containment approach is more appropriate. This paper is a discussion of a DOE funded research and development study [1] on the feasibility of in situ construction bottom barrier containment structures in soil under and around large contaminated sites. The evaluated bottom barrier method begins with a conventional slurry trench around the perimeter of a site. The method utilizes high-density slurry grout and a cable saw mechanism to make a controlled horizontal cut at the base of the slurry trench. Gravity alone forces the dense slurry into the horizontal cut and causes the entire block of earth to literally float in a slurry grout that cures into an impermeable barrier material. The work included evaluation of a completed field test that floated a 50-ton block of earth, development of a computer model of the process, evaluation of structural hydraulic and shearing forces on the earth block, measurement of friction and cutting forces in a field test, hardware design drawings, cost analysis, and an ASME review. The study evaluated issues such as scalability, and adaptability to various geologic conditions such as soil types and layers, hills, rocks, saturated soil, faults, waste density variations, fractures and unconsolidated soil formations. A method to measure the integrity of the barrier both after construction and periodically in the future was also evaluated. Barrier durability, erosion, bio-penetration, and moisture related cracking, and response to earth movements is also considered. Reactive and adsorptive chemistry to relatively thick layers of barrier material are proposed that may further improve long term containment. (authors)

  1. Will the balance of power shift among native eastern Pacific estuary ecosystem engineers with the introduced bopyrid isopod parasite orthione griffenis?

    EPA Science Inventory

    The blue mud shrimp, Upogebia pugettensis, the bay ghost shrimp, Neotrypaea californiensis, and eelgrass, Zostera marina are endemic ecosystem engineers that define the ecological structure and function of estuaries along the Pacific coast of the US as significantly as do marshes...

  2. Subseabed Radioactive Waste Disposal Feasibility Program: ocean engineering challenges for the 80's

    SciTech Connect

    Talbert, D. M.

    1980-01-01

    The objective of the Subseabed Disposal Program is to assess the feasibility of disposing of high-level radioactive wastes or spent fuel in suitable geologic formations beneath the deep ocean floor. The program is entering a phase which will address engineering feasibility. While the current phase of the program to determine the scientific and environmental feasibility of the concept is not yet complete, activities to assess the engineering aspects are being initiated in parallel to facilitate the development of the concept on a time scale commensurate with other related programs both in the United States and abroad. It is anticipated that engineering aspects will become the central focus of the program during the early 80's and will continue so through the establishment of a pilot-plant level activity which could occur by the mid-90's.

  3. Krypton-85 hydrofracture engineering feasibility and safety evaluation

    SciTech Connect

    Peretz, F.J.; Muller, M.E.; Pan, P.Y.

    1981-07-01

    Engineering studies have been made to determine the hazards associated with the disposal of /sup 85/Kr using the hydrofracture process. To assess the hazards, an effort has been made to identify the equipment required to entrain and dissolve the noble gas into the grout stream at hydrofracture pressure (up to 350 bar). Off-the-shelf or slightly modified equipment has been identified for safe and effective compression and gas-grout mixing. Each monthly injection disposes of 1.6 x 10/sup 6/ Ci of /sup 85/Kr. By connecting only one gas cylinder to the injection system at a time, the maximum amount of krypton likely to be released as a result of equipment failure is limited to 128,000 Ci. An evaluation by Los Alamos Technical Associates shows that releasing this amount of gas in less than one hour under worst-case meteorological conditions through a 30-m stack would result in a whole-body dose of 170 millirem at a distance of 1 km from the facility. A krypton collection and recovery system can further reduce this dose to 17 millirem; increasing the distance to the site boundary to 3 km can also reduce the dose by a factor of ten. Lung and skin dose estimates are 1.6 and 120 times the whole-body dose, respectively. These are all worst-case values; releases under more typical conditions would result in a significantly lower dose. No insurmountable safety or engineering problems have been identified.

  4. Program to investigate the engineering feasibility of extracting energy from shallow magma bodies

    SciTech Connect

    Carson, C.C.; Allen, A.D.

    1984-01-01

    A new program, sponsored by the Department of Energy's Geothermal and Hydropower Technologies Division, has begun to investigate the engineering feasibility of extracting energy from shallow magma bodies. This program follows a previous investigation of the scientific feasibility of using magma and differs from it in focus. The current program is directed toward determining whether magma energy can be extracted economically. In the first year of the program, the three most promising sites for a long term experiment will be characterized; the research and development tasks that will be required will be identified; and a program plan outlining the entire feasibility study will be compiled.

  5. Expanding Metabolic Engineering Algorithms Using Feasible Space and Shadow Price Constraint Modules

    PubMed Central

    Tervo, Christopher J.; Reed, Jennifer L.

    2014-01-01

    While numerous computational methods have been developed that use genome-scale models to propose mutants for the purpose of metabolic engineering, they generally compare mutants based on a single criteria (e.g., production rate at a mutants maximum growth rate). As such, these approaches remain limited in their ability to include multiple complex engineering constraints. To address this shortcoming, we have developed feasible space and shadow price constraint (FaceCon and ShadowCon) modules that can be added to existing mixed integer linear adaptive evolution metabolic engineering algorithms, such as OptKnock and OptORF. These modules allow strain designs to be identified amongst a set of multiple metabolic engineering algorithm solutions that are capable of high chemical production while also satisfying additional design criteria. We describe the various module implementations and their potential applications to the field of metabolic engineering. We then incorporated these modules into the OptORF metabolic engineering algorithm. Using an Escherichia coli genome-scale model (iJO1366), we generated different strain designs for the anaerobic production of ethanol from glucose, thus demonstrating the tractability and potential utility of these modules in metabolic engineering algorithms. PMID:25478320

  6. A feasibility study of a new ATREX engine system of aft-turbine configuration

    NASA Astrophysics Data System (ADS)

    Isomura, Kousuke; Omi, Junsuke; Tanatsugu, Nobuhiro; Sato, Tetsuya; Kobayashi, Hiroaki

    2002-07-01

    A feasibility of ATREX (Air-Turbo-Ram Expander cycle) engine with conventional aft-turbine configuration has been studied to be developed in about 10 years, if the development project has started under enough resources. The novel tip-turbine of the original ATREX engine is replaced by a conventional aft-turbine, and the maximum turbine inlet temperature (TTT) is reduced to 1200K, to realize the engine by only using approved metal technologies of modern jet engines. The capability of the performance has been shown by parametric studies by changing components' design parameters. The study shows that the performance of the ATREX engine is not less than that of pre-cooled turbo jet. Some technical issues on developing the new ATREX engine have been addressed. The most important issue would come from the transient total temperature change due to the rapid acceleration from sea level static (SLS) condition (288K) to Mach 6 at 30km of altitude (1680K) in 6 minutes. The deformation due to transient thermal expansion has to be controlled. Especially, the change of the tip clearance and the clearance between rotors and stators are pointed out to be important design issues. The ATREX engine, which has shorter axial length and simpler rotor, has structural advantage over turbo jet.

  7. Demonstration of the mechanical feasibility of the WLVEC engine. Final report

    SciTech Connect

    Steelman, G.

    1980-05-01

    From June, 1977 to May, 1980, a building and testing research project has taken place to determine whether the parachute powered water low velocity energy converter WLVEC engine would be a mechanically feasible device to extract usable mechanical energy from the kinetic energy resource found in unconstrained, low velocity, massive flowing streams, i.e., ocean currents, tidal currents, and flowing rivers. A device has been built. The parachute powered loop component has been tested in a flowing river. The corresponding power extraction wheels component has been shop tested. Due to budgetary limitations, a comprehensive in-water field test was not performed. However, it was established that usable shaft RPM/torque is developed via the WLVEC process. A previous demonstration test was conducted in 1976 under the auspices of the Florida Solar Energy Center. That test actually produced electricity from 1/2 knot to 3 knots in the Atlantic Ocean. Taking all available data and results into consideration, it has been established that it is mechanically and technically feasible to develop usable mechanical power and electrical power with the WLVEC engine. It is recommended that further testing of the 1980 model WLVEC engine be done as detailed in the Appendix: Requested Proposal RJ-0-9213-1 Phase II Device Testing and Data Acquisition. Phase II testing will acquire those operational force/power data that were unobtainable with Phase I funding. It is also recommended that a systems engineering study be conducted that is directed towards designing a 10 MW WLVEC plant.

  8. Engine Company Evaluation of Feasibility of Aircraft Retrofit Water-Injected Turbomachines

    NASA Technical Reports Server (NTRS)

    Becker, Arthur

    2006-01-01

    This study supports the NASA Glenn Research Center and the U.S. Air Force Research Laboratory in their efforts to evaluate the effect of water injection on aircraft engine performance and emissions. In this study, water is only injected during the takeoff and initial climb phase of a flight. There is no water injection during engine start or ground operations, nor during climb, cruise, descent, or landing. This study determined the maintenance benefit of water injection during takeoff and initial climb and evaluated the feasibility of retrofitting a current production engine, the PW4062 (Pratt & Whitney, East Hartford, CT), with a water injection system. Predicted NO(x) emissions based on a 1:1 water-tofuel ratio are likely to be reduced between 30 to 60 percent in Environmental Protection Agency parameter (EPAP). The maintenance cost benefit for an idealized combustor water injection system installed on a PW4062 engine in a Boeing 747-400ER aircraft (The Boeing Company, Chicago, IL) is computed to be $22 per engine flight hour (EFH). Adding water injection as a retrofit kit would cost up to $375,000 per engine because of the required modifications to the fuel system and addition of the water supply system. There would also be significant nonrecurring costs associated with the development and certification of the system that may drive the system price beyond affordability.

  9. Feasibility of Biomarker Studies for Engineered Nanoparticles: What Can Be Learned from Air Pollution Research

    PubMed Central

    Li, Ning; Nel, Andre E.

    2011-01-01

    Objective Occupational exposure to engineered nanoparticles (NP) may pose health risks to the workers. This article is to discuss the feasibility of identifying biomarkers that are associated with NP exposure. Methods Scientific literature on the adverse health effects of ambient ultrafine particles (UFP) and NP was reviewed to discuss the feasibility of conducting biomarker studies to identify NP-induced early biological changes. Results Various approaches for biomarker studies have been identified, including potential injury pathways that need to be considered and the methodologies that may be used for such studies. Conclusions Although NP may have novel mechanisms of injury, much can be learned from our experience in studying UFP. Oxidative stress-related pathways could be an important consideration for identifying NP-associated biomarkers and one of the most effective approaches for such studies may be proteome profiling. PMID:21654422

  10. Idaho Nuclear Technology and Engineering Center Newly Generated Liquid Waste Demonstration Project Feasibility Study

    SciTech Connect

    Herbst, A.K.

    2000-02-01

    A research, development, and demonstration project for the grouting of newly generated liquid waste (NGLW) at the Idaho Nuclear Technology and Engineering Center is considered feasible. NGLW is expected from process equipment waste, decontamination waste, analytical laboratory waste, fuel storage basin waste water, and high-level liquid waste evaporator condensate. The potential grouted waste would be classed as mixed low-level waste, stabilized and immobilized to meet RCRA LDR disposal in a grouting process in the CPP-604 facility, and then transported to the state.

  11. A hingeless rotor XV-15 design integration feasibility study. Volume 1: Engineering design studies

    NASA Technical Reports Server (NTRS)

    Magee, J. P.; Alexander, H. R.

    1978-01-01

    A design integration feasibility study was carried out to investigate what modifications to the basic XV-15 were necessary to accomplish a flight demonstration of the XV-15 with a Boeing hingeless rotor. Also investigated were additional modifications which would exploit the full capability provided by the combination of the new rotor and the existing T53 engine. An evaluation of the aircraft is presented and the data indicate improved air vehicle performance, acceptable aeroelastic margins, lower noise levels and improved flying qualities compared with the XV-15 aircraft. Inspection of the rotor system data provided shows an essentially unlimited life rotor for the flight spectrum anticipated for the XV-15.

  12. Feasibility Investigation on the Development of a Structural Damage Diagnostic and Monitoring System for Rocket Engines

    NASA Technical Reports Server (NTRS)

    Shen, Ji Y.; Sharpe, Lonnie, Jr.

    1998-01-01

    The research activity for this project is mainly to investigate the necessity and feasibility to develop a structural health monitoring system for rocket engines, and to carry out a research plan for further development of the system. More than one hundred technical papers have been searched and reviewed during the period. We concluded after this investigation that adding a new module in NASA's existing automated diagnostic system to monitor the healthy condition of rocket engine structures is a crucial task, and it's possible to develop such a system based upon the vibrational-based nondestructive damage assessment techniques. A number of such techniques have been introduced. Their advantages and disadvantages are also discussed. A global research plan has been figured out. As the first step of the overall research plan, a proposal for the next fiscal year has been submitted.

  13. GEEF: a geothermal engineering and economic feasibility model. Description and user's manual

    SciTech Connect

    Not Available

    1982-09-01

    The model is designed to enable decision makers to compare the economics of geothermal projects with the economics of alternative energy systems at an early stage in the decision process. The geothermal engineering and economic feasibility computer model (GEEF) is written in FORTRAN IV language and can be run on a mainframe or a mini-computer system. An abbreviated version of the model is being developed for usage in conjunction with a programmable desk calculator. The GEEF model has two main segments, namely (i) the engineering design/cost segment and (ii) the economic analysis segment. In the engineering segment, the model determines the numbers of production and injection wells, heat exchanger design, operating parameters for the system, requirement of supplementary system (to augment the working fluid temperature if the resource temperature is not sufficiently high), and the fluid flow rates. The model can handle single stage systems as well as two stage cascaded systems in which the second stage may involve a space heating application after a process heat application in the first stage.

  14. Engineering feasibility analysis for in-situ stabilization of Burrell Township site residues. [UMTRA

    SciTech Connect

    Not Available

    1982-11-01

    The Burrell Township site, located in western Pennsylvania, received approximately 11,600 tons of radioactively-contaminated material in late 1956 and early 1957 from the Vitro Manufacturing Company's operations in Canonsburg, Pennsylvania. WESTON was requested to conduct an engineering study to determine the feasibility of stabilizing the site in accordance with the US Environmental Protection Agency's (EPA) interim and proposed standards (45 FR 27366--27368, April 22, 1980, and 46 FR 2556--2563, January 9, 1981). The scope of this study is limited to those alternatives that can be implemented on the site and will not require removal and offsite disposal of radioactively-contaminated material. Four alternatives for control of the radioactive material at the Burrell site were considered and evaluated, as follows: 1. Site stabilization and closure. 2. Site control and containment. 3. Waste excavation and encapsulation. 4. Waste excavation, incineration, and encapsulation. 2 refs., 32 figs., 12 tabs.

  15. Conceptual Design and Feasibility of Foil Bearings for Rotorcraft Engines: Hot Core Bearings

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2007-01-01

    Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include oil-free microturbines, motors, generators and turbochargers. The driving forces for integrating gas foil bearings into these high-speed systems are the benefits promised by removing the oil lubrication system. Elimination of the oil system leads to reduced emissions, increased reliability, and decreased maintenance costs. Another benefit is reduced power plant weight. For rotorcraft applications, this would be a major advantage, as every pound removed from the propulsion system results in a payload benefit.. Implementing foil gas bearings throughout a rotorcraft gas turbine engine is an important long-term goal that requires overcoming numerous technological hurdles. Adequate thrust bearing load capacity and potentially large gearbox applied radial loads are among them. However, by replacing the turbine end, or hot section, rolling element bearing with a gas foil bearing many of the above benefits can be realized. To this end, engine manufacturers are beginning to explore the possibilities of hot section gas foil bearings in propulsion engines. This overview presents a logical follow-on activity by analyzing a conceptual rotorcraft engine to determine the feasibility of a foil bearing supported core. Using a combination of rotordynamic analyses and a load capacity model, it is shown to be reasonable to consider a gas foil bearing core section. In addition, system level foil bearing testing capabilities at NASA Glenn Research Center are presented along with analysis work being conducted under NRA Cooperative Agreements.

  16. Feasibility Demonstration of a 445N High-Performance Rocket Engine

    NASA Technical Reports Server (NTRS)

    Appel, Marshall A.; Schoenman, Leonard; Franklin, Jerrold E.; Lansaw, P. Tina

    1989-01-01

    A program to demonstrate the feasibility of a high-performance 445 Newton (100 lb(sub f)) NTO/NMH rocket engine is presented. An existing high-performance injector was coupled with three different thrust chambers to acquire test data for the program. A stainless-steel sea-level chamber was used for test stand checkout, calibration and initial injector performance determinations. Two high-temperature iridium lined rhenium thrust chambers were used to determine altitude performance and durability. The first chamber was tested for a total duration of 3381 s and the second was tested for a total duration of 15,000 s with no measurable degradation. Extrapolation of epsilon = 44:1 experimental data to the recommended epsilon = 467:1 expansion nozzle, using the JANNAF methodology, showed that a performance of 3138 to 3167 N-s/kg (320 to 323 lb(sub f-s)/lb(sub m) could be achieved with the present design. Recommendations are presented which would allow a redesigned engine to achieve the 3195 N-s/kg (326 lb(sub f-s)/lb(sub m)) program goal.

  17. Engineering Feasibility and Trade Studies for the NASA/VSGC MicroMaps Space Mission

    NASA Technical Reports Server (NTRS)

    Abdelkhalik, Ossama O.; Nairouz, Bassem; Weaver, Timothy; Newman, Brett

    2003-01-01

    Knowledge of airborne CO concentrations is critical for accurate scientific prediction of global scale atmospheric behavior. MicroMaps is an existing NASA owned gas filter radiometer instrument designed for space-based measurement of atmospheric CO vertical profiles. Due to programmatic changes, the instrument does not have access to the space environment and is in storage. MicroMaps hardware has significant potential for filling a critical scientific need, thus motivating concept studies for new and innovative scientific spaceflight missions that would leverage the MicroMaps heritage and investment, and contribute to new CO distribution data. This report describes engineering feasibility and trade studies for the NASA/VSGC MicroMaps Space Mission. Conceptual studies encompass: 1) overall mission analysis and synthesis methodology, 2) major subsystem studies and detailed requirements development for an orbital platform option consisting of a small, single purpose spacecraft, 3) assessment of orbital platform option consisting of the International Space Station, and 4) survey of potential launch opportunities for gaining assess to orbit. Investigations are of a preliminary first-order nature. Results and recommendations from these activities are envisioned to support future MicroMaps Mission design decisions regarding program down select options leading to more advanced and mature phases.

  18. Injectable Tissue-Engineered Pulmonary Heart Valve Implantation Into the Pig Model: A Feasibility Study

    PubMed Central

    Schlegel, Franziska; Salameh, Aida; Oelmann, Katja; Halling, Michelle; Dhein, Stefan; Mohr, Friedrich W.; Dohmen, Pascal M.

    2015-01-01

    Background Transcatheter pulmonary valve replacement is currently performed in clinical trials, but is limited by the use of glutaraldehyde-treated bioprostheses. This feasibility study was performed to evaluate delivery-related tissue distortion during implantation of tissue-engineered (TE) heart valves. Material/Methods The injectable TE heart valve was mounted on a self-expanding nitinol stent (n=7) and delivered into the pulmonary position in 7 pigs, (weight 26 to 31 kg), performing a sternotomy or limited lateral thoracotomy. Prior to implantation, the injectable TE heart valves were crimped and inserted into an applicator. Positioning of the implants was guided by fluoroscopy, and after careful deployment, angiographic examination was performed to evaluate the correct delivered position. Hemodynamic measurements were performed by epicardial echocardiography. Finally, the animals were sacrificed and the injectable TE heart valves were inspected by gross examination and histological examination. Results Orthotopic deliveries of the injectable TE heart valves were all successful performed, expect in 1 where the valve migrated due to a discrepancy between pulmonary valve annulus size and injectable TE valve size. Angiographic evaluation (n=6) showed normal valve function, supported by epicardial echocardiography in which no increased flow velocity was measured, neither trans- nor paravalvular regurgitation. Histological evaluation demonstrated absence of tissue damage from the delivery process. Conclusions Transcatheter implantation of an injectable TE heart valve seems to be possible without tissue distortion due to the delivery system. PMID:26104851

  19. CARS temperature measurements in the fuel preburner of the Space Shuttle main engine: A feasibility study

    NASA Technical Reports Server (NTRS)

    Beiting, E. J.; Luthe, J. C.

    1983-01-01

    This report discusses the feasibility of making temperature profile measurements in the fuel preburner of the main engine of the space shuttle (SSME) using coherent anti-Stokes Raman spectroscopy (CARS). The principal thrust of the work is to identify problems associated with making CARS measurements in high temperature gas phase hydrogen at very high pressures (approx 400 atmospheres). To this end a theoretical study was made of the characteristics of the CAR spectra of H2 as a function of temperature and pressure and the accuracy with which temperatures can be extracted from this spectra. In addition the experimental problems associated with carrying out these measurements on a SSME at NSTL were identified. A conceptual design of a CARS system suitable for this work is included. Many of the results of the calculations made in this report are plotted as a function of temperature. In the course of presenting these results, it was necessary to decide whether the number of density or the pressure should be treated as a fixed parameter.

  20. Embedded Acoustic Sensor Array for Engine Fan Noise Source Diagnostic Test: Feasibility of Noise Telemetry via Wireless Smart Sensors

    NASA Technical Reports Server (NTRS)

    Zaman, Afroz; Bauch, Matthew; Raible, Daniel

    2011-01-01

    Aircraft engines have evolved into a highly complex system to meet ever-increasing demands. The evolution of engine technologies has primarily been driven by fuel efficiency, reliability, as well as engine noise concerns. One of the sources of engine noise is pressure fluctuations that are induced on the stator vanes. These local pressure fluctuations, once produced, propagate and coalesce with the pressure waves originating elsewhere on the stator to form a spinning pressure pattern. Depending on the duct geometry, air flow, and frequency of fluctuations, these spinning pressure patterns are self-sustaining and result in noise which eventually radiate to the far-field from engine. To investigate the nature of vane pressure fluctuations and the resulting engine noise, unsteady pressure signatures from an array of embedded acoustic sensors are recorded as a part of vane noise source diagnostics. Output time signatures from these sensors are routed to a control and data processing station adding complexity to the system and cable loss to the measured signal. "Smart" wireless sensors have data processing capability at the sensor locations which further increases the potential of wireless sensors. Smart sensors can process measured data locally and transmit only the important information through wireless communication. The aim of this wireless noise telemetry task was to demonstrate a single acoustic sensor wireless link for unsteady pressure measurement, and thus, establish the feasibility of distributed smart sensors scheme for aircraft engine vane surface unsteady pressure data transmission and characterization.

  1. CF6 jet engine performance improvement program. Task 1: Feasibility analysis

    NASA Technical Reports Server (NTRS)

    Fasching, W. A.

    1979-01-01

    Technical and economic engine improvement concepts selected for subsequent development include: (1) fan improvement; (2) short core exhaust; (3) HP turbine aerodynamic improvement; (4) HP turbine roundness control; (5) HP turbine active clearance control; and (6) cabin air recirculation. The fuel savings for the selected engine modification concepts for the CF6 fleet are estimated.

  2. rRNA (rrn) Operon-Engineered Bacillus subtilis as a Feasible Test Organism for Antibiotic Discovery

    PubMed Central

    Tanaka, Yukinori; Nanamiya, Hideaki; Yano, Koichi; Kakugawa, Koji; Kawamura, Fujio

    2013-01-01

    Bacillus subtilis contains 10 rRNA (rrn) operons. We found that rRNA operon-engineered B. subtilis strain RIK543, with only the rrnO operon, is specifically hypersensitive to RNA polymerase inhibitors such as rifamycin SV and rifampin (80-fold and 20-fold, respectively). In pilot screening experiments, we found actinomycete isolates successfully at an incidence of 1.9% (18/945) that produced antibacterials that were detectable only with RIK543 as the test organism. Strain RIK543 may be a feasible test organism for the discovery of novel RNA polymerase inhibitors. PMID:23335737

  3. Engineering feasibility analysis for in-situ stabilization of Canonsburg residues. [UMTRA project

    SciTech Connect

    Not Available

    1982-01-01

    The US Department of Energy is considering several methods for carrying out remedial actions in Canonsburg, Pennsylvania, at the site of an inactive uranium-processing mill. The main objective of this study is to determine the feasibility of in-situ stabilization as the remedial action. In-situ stabilization is an alternative to site decontamination and offsite disposal. The problems associated with offsite hauling of large quantities of contaminated material and with the location and development of a new disposal site could be avoided by the implementation of an in-situ stabilization concept. In addition, the in-situ approach would be more cost-effective than offsite disposal. This study will establish that a technically feasible and implementable in-situ stabilization concept can be developed that meets regulatory requirements and is cost effective. This study in no way commits the DOE to implement any specific actions described herein. 11 refs., 30 figs., 24 tabs.

  4. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    SciTech Connect

    John Pratapas; Daniel Mather; Anton Kozlovsky

    2007-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen's significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an analysis of test results indicates that hydrogen enhanced natural gas HCCI (versus neat natural gas HCCI at comparable stoichiometry) had the following characteristics: (1) Substantially lower intake temperature needed for stable HCCI combustion; (2) Inconclusive impact on engine BMEP and power produced; (3) Small reduction in the thermal efficiency of the engine; (4) Moderate reduction in the unburned hydrocarbons in the exhaust; (5) Slight increase in NOx emissions in the exhaust; (6) Slight reduction in CO2 in the exhaust; and (7) Increased knocking at rich stoichiometry. The major accomplishments and findings from the project can be summarized as follows: (1) A model was calibrated for accurately predicting heat release rate and peak pressures for HCCI combustion when operating on hydrogen and natural gas blends. (2) A single cylinder research engine was thoroughly mapped to compare performance and emissions for micro-pilot natural gas compression ignition, and HCCI combustion for neat natural gas versus blends of natural gas and hydrogen. (3) The benefits of using hydrogen to extend, up to a limit, the stable operating window for HCCI combustion of natural gas at higher intake pressures, leaner air to fuel ratios or lower inlet temperatures was documented.

  5. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    SciTech Connect

    Pratapas, John; Mather, Daniel; Kozlovsky, Anton

    2013-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen’s significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an analysis of test results indicates that hydrogen enhanced natural gas HCCI (versus neat natural gas HCCI at comparable stoichiometry) had the following characteristics: • Substantially lower intake temperature needed for stable HCCI combustion • Inconclusive impact on engine BMEP and power produced, • Small reduction in the thermal efficiency of the engine, • Moderate reduction in the unburned hydrocarbons in the exhaust, • Slight increase in NOx emissions in the exhaust, • Slight reduction in CO2 in the exhaust. • Increased knocking at rich stoichiometry The major accomplishments and findings from the project can be summarized as follows: 1. A model was calibrated for accurately predicting heat release rate and peak pressures for HCCI combustion when operating on hydrogen and natural gas blends. 2. A single cylinder research engine was thoroughly mapped to compare performance and emissions for micro-pilot natural gas compression ignition, and HCCI combustion for neat natural gas versus blends of natural gas and hydrogen.

  6. Bio-geomorphology of estuaries: the need for understanding the balance between ecosystem engineering, physical forcing and biomechanical species interactions

    NASA Astrophysics Data System (ADS)

    Bouma, Tjeerd; Balke, Thorsten; van Belzen, Jim; Cozzoli, Francesco; Suykerbuyk, Wouter; van Katwijk, Marieke; Temmerman, Stijn; Herman, Peter

    2013-04-01

    The estuarine environment is strongly affected by the hydrodynamic forces from currents and waves, which often form both a resource and a stress to the organisms inhabiting these areas. Organisms that inhabit these areas interact with these physical forces, and may thereby modify their abiotic environment. This is referred to as ecosystem engineering (EE), which may result in locally improved growing conditions for the organisms. By their activities, ecosystem engineers (EE's) can have major influence on sediment dynamics in the coastal ecosystems and may create self-organised bio-geomorphologic landscapes. However, the physical-driven sediment dynamics may also impose control over organism establishment and performance. And on top of that, ecosystem engineering organisms may affect the occurrence of each other via their effect on the environment (i.e., 'biomechanical warfare'). The combination of these 3 types of interactions makes the dynamics of biogeomorphic ecosystems complex to understand and model, and restoration of biogeomorphic ecosystems hard to accomplish. In our presentation we will highlight 3 aspects that we see as crucial to improve our understanding, modelling and restoration of biogeomorphic ecosystems: (1) the possibility to generalise EE-effects across species (2) identifying to which extent physical forcing may enable vs. restrict EE-effects (3) understanding the biological and physical thresholds to the establishment of EE's, and the long-term dynamics of biogemorphic ecosystems. Each of these aspects will be discussed based on experimental results.

  7. Experimental research made during a city cycle on the feasibility of electrically charged SI engines

    NASA Astrophysics Data System (ADS)

    Kocsis, Levente; Burnete, Nicolae

    2014-06-01

    The paper presents experimental research on performance improvements in a city cycle (operating mostly transient) of a compact class vehicle equipped with a turbocharged SI engine which had attached an electric charger, to improve engine response at low operational speeds. During tests, functional parameters, energy consumption of the electric charger and vehicle performances were measured while driving in two operating conditions: with active and inactive electric charger. The tests were carried out on a well-defined path, in the same driving style, by the same driver.

  8. Introduction to Estuaries

    EPA Science Inventory

    Estuaries, although minor geographical features at the global scale, have major importance for society and the worlds economies. This chapter introduces estuaries by presenting an overview of definitions, origins, physical, chemical and ecological attributes, and the interaction...

  9. Introduction to Estuaries

    EPA Science Inventory

    Estuaries, although minor geographical features at the global scale, have major importance for society and the world’s economies. This chapter introduces estuaries by presenting an overview of definitions, origins, physical, chemical and ecological attributes, and the interaction...

  10. The feasibility of ureteral tissue engineering using autologous veins: an orthotopic animal model with long term results

    PubMed Central

    2014-01-01

    Background In an earlier study we demonstrated the feasibility to create tissue engineered venous scaffolds in vitro and in vivo. In this study we investigated the use of tissue engineered constructs for ureteral replacement in a long term orthotopic minipig model. In many different projects well functional ureretal tissue was established using tissue engineering in animals with short-time follow up (12 weeks). Therefore urothelial cells were harvested from the bladder, cultured, expanded in vitro, labelled with fluorescence and seeded onto the autologous veins, which were harvested from animals during a second surgery. Three days after cell seeding the right ureter was replaced with the cell-seeded matrices in six animals, while further 6 animals received an unseeded vein for ureteral replacement. The animals were sacrificed 12, 24, and 48 weeks after implantation. Gross examination, intravenous pyelogram (IVP), H&E staining, Trichrome Masson’s Staining, and immunohistochemistry with pancytokeratin AE1/AE3, smooth muscle alpha actin, and von Willebrand factor were performed in retrieved specimens. Results The IVP and gross examination demonstrated that no animals with tissue engineered ureters and all animals of the control group presented with hydronephrosis after 12 weeks. In the 24-week group, one tissue engineered and one unseeded vein revealed hydronephrosis. After 48 weeks all tissue engineered animals and none of the control group showed hydronephrosis on the treated side. Histochemistry and immunohistochemistry revealed a multilayer of urothelial cells attached to the seeded venous grafts. Conclusions Venous grafts may be a potential source for ureteral reconstruction. The results of so far published ureteral tissue engineering projects reveal data up to 12 weeks after implantation. Even if the animal numbers of this study are small, there is an increasing rate of hydronephrosis revealing failure of ureteral tissue engineering with autologous matrices in time points longer than 3 months after implantation. Further investigations have to prove adequate clinical outcome and appropriate functional long-term results. PMID:25381044

  11. Predicting Bankfull Discharge in Ungauged Estuaries by Explaining the Physical Relation Between the Morphology and Hydrology of Estuaries

    NASA Astrophysics Data System (ADS)

    Gisen, J.; Savenije, H.

    2013-12-01

    River discharge is a very important parameter in morphological and hydrodynamic studies of estuaries. However, it is always difficult to accurately measure river discharge, and in particular the bankfull discharge in estuaries where the tidal discharge dominates over river discharge. Until today, little research has been done in finding a simple and useful approach to estimate the river discharge in the tidal region, and most of the previous studies focused on the river regime. In this study, we found that there appear to be empirical relations that link together the morphology and hydrology of estuaries, which can be used to estimate river discharge with the least amount of data available. The aims of this study are: 1) to discover the physical explanation for the empirical relation that exists between geometrical characteristics of estuaries and the bankfull flood discharge; and 2) to estimate bankfull discharge in estuaries from the relationship. The physical connection between the estuaries and river regime is found by incorporating the estuary shape analysis and tidal dynamic analysis to Lacey's hydraulic geometry theory. Relationship between the estuary depth and the bankfull river discharge has been analyzed in 19 estuaries around the world (with 9 recently surveyed estuaries). In this study, the discharge data (from gauging station located further upstream) were adjusted by a projection approach to improve the discharge measurement. The outcome of the relationship was compared to Lacey's theory of hydraulic geometry. From the analysis, it shows that the depth of an estuary is a function of the bankfull flood discharge to the power of 1/3 which indicates an agreement with Lacey's formula. With the physical explanation, engineers would be able to estimate flood discharge characteristics from estuary shape indicators. This could be very useful to estimate the flood discharge in ungauged estuaries on the basis of readily available data. In order to verify the accuracy of the relation, existing and new measurement data from estuaries worldwide will be collected and compiled to strengthen the reliability of this finding.

  12. JT8D and JT9D jet engine performance improvement program. Task 1: Feasibility analysis

    NASA Technical Reports Server (NTRS)

    Gaffin, W. O.; Webb, D. E.

    1979-01-01

    JT8D and JT9D component performance improvement concepts which have a high probability of incorporation into production engines were identified and ranked. An evaluation method based on airline payback period was developed for the purpose of identifying the most promising concepts. The method used available test data and analytical models along with conceptual/preliminary designs to predict the performance improvements, weight, installation characteristics, cost for new production and retrofit, maintenance cost, and qualitative characteristics of candidate concepts. These results were used to arrive at the concept payback period, which is the time required for an airline to recover the investment cost of concept implementation.

  13. Engineering practice variation through provider agreement: a cluster-randomized feasibility trial

    PubMed Central

    McCarren, Madeline; Twedt, Elaine L; Mansuri, Faizmohamed M; Nelson, Philip R; Peek, Brian T

    2014-01-01

    Purpose Minimal-risk randomized trials that can be embedded in practice could facilitate learning health-care systems. A cluster-randomized design was proposed to compare treatment strategies by assigning clusters (eg, providers) to favor a particular drug, with providers retaining autonomy for specific patients. Patient informed consent might be waived, broadening inclusion. However, it is not known if providers will adhere to the assignment or whether institutional review boards will waive consent. We evaluated the feasibility of this trial design. Subjects and methods Agreeable providers were randomized to favor either hydrochlorothiazide or chlorthalidone when starting patients on thiazide-type therapy for hypertension. The assignment applied when the provider had already decided to start a thiazide, and providers could deviate from the strategy as needed. Prescriptions were aggregated to produce a provider strategy-adherence rate. Results All four institutional review boards waived documentation of patient consent. Providers (n=18) followed their assigned strategy for most of their new thiazide prescriptions (n=138 patients). In the favor hydrochlorothiazide group, there was 99% adherence to that strategy. In the favor chlorthalidone group, chlorthalidone comprised 77% of new thiazide starts, up from 1% in the pre-study period. When the assigned strategy was followed, dosing in the recommended range was 48% for hydrochlorothiazide (2550 mg/day) and 100% for chlorthalidone (12.525.0 mg/day). Providers were motivated to participate by a desire to contribute to a comparative effectiveness study. A study promotional mug, provider information letter, and interactions with the site investigator were identified as most helpful in reminding providers of their study drug strategy. Conclusion Providers prescribed according to an assigned drug-choice strategy most of the time for the purpose of a comparative effectiveness study. This simple design could facilitate research participation and behavior change in non-research clinicians. Waiver of patient consent can broaden the representation of patients, providers, and settings. PMID:25414573

  14. Application of a three-dimensional water quality model to the James Estuary. Master's thesis

    SciTech Connect

    Larsen, C.J.

    1993-05-01

    Water quality models continue to increase in options and accuracy as super computer access becomes a reality for water quality management. The US Army Corps of Engineers (USACE) Waterways Experiment Station (WES), in Vicksburg, Mississippi has developed a state of the art modeling framework for simulating the hydrodynamics and water quality standards of the Chesapeake Bay. As environmental engineers focus more attention on Bays tributaries this year, this complicated model must be accurately applied to the major freshwater rivers emptying into the Bay. To discover the feasibility of applying the models to a smaller estuary system, the Chesapeake Bay model was reconfigured and applied to the James River Estuary in Virginia. The alteration mandated input file data reconstruction and development, basin mapping, and site specific code adjustments for the models and the postprocessor. The model size and memory needs dictate super computer enrollment for accurate and timely system utilization. The model was calibrated using salinity data on the James Estuary, and verified by dissolved oxygen and chlorophyll a responses to nutrient loadings. A model sensitivity analysis of the results was conducted to ensure that reliable results were obtained.

  15. Boron neutron capture therapy applied to advanced breast cancers: Engineering simulation and feasibility study of the radiation treatment protocol

    NASA Astrophysics Data System (ADS)

    Sztejnberg Goncalves-Carralves, Manuel Leonardo

    This dissertation describes a novel Boron Neutron Capture Therapy (BNCT) application for the treatment of human epidermal growth factor receptor type 2 positive (HER2+) breast cancers. The original contribution of the dissertation is the development of the engineering simulation and the feasibility study of the radiation treatment protocol for this novel combination of BNCT and HER2+ breast cancer treatment. This new concept of BNCT, representing a radiation binary targeted treatment, consists of the combination of two approaches never used in a synergism before. This combination may offer realistic hope for relapsed and/or metastasized breast cancers. This treatment assumes that the boronated anti-HER2 monoclonal antibodies (MABs) are administrated to the patient and accumulate preferentially in the tumor. Then the tumor is destroyed when is exposed to neutron irradiation. Since the use of anti-HER2 MABs yields good and promising results, the proposed concept is expected to amplify the known effect and be considered as a possible additional treatment approach to the most severe breast cancers for patients with metastasized cancer for which the current protocol is not successful and for patients refusing to have the standard treatment protocol. This dissertation makes an original contribution with an integral numerical approach and proves feasible the combination of the aforementioned therapy and disease. With these goals, the dissertation describes the theoretical analysis of the proposed concept providing an integral engineering simulation study of the treatment protocol. An extensive analysis of the potential limitations, capabilities and optimization factors are well studied using simplified models, models based on real CT patients' images, cellular models, and Monte Carlo (MCNP5/X) transport codes. One of the outcomes of the integral dosimetry assessment originally developed for the proposed treatment of advanced breast cancers is the implementation of BNCT for HER2+ breast cancers for deep seated tumors using MITRII-FCB facility with an 8 cm diameter beam (port closest-to-tumor position), with boron concentrations in the tumor higher than 32 mug/g, and for a tumor-to-healthy tissue boron concentration ratio of 8:1. The therapeutic ratios for the proposed treatment would be higher than five for skin and adipose tissue and higher than three for tumor surrounding fibroglandular tissue. The microdosimetry study shows potential improvements in the therapeutic ratios based on the expected sub-cellular boron biodistributions. The engineering simulation study of clinical cases shows the advantages of using BNCT for HER+ breast cancers. Assuming an assured high efficiency of the boron agent delivery, the proposed concept can be considered for stage IV HER2+ breast cancers in treating the metastasized tumors in brain, head and neck, and lungs.

  16. Genome engineering in Vibrio cholerae: a feasible approach to address biological issues.

    PubMed

    Val, Marie-Eve; Skovgaard, Ole; Ducos-Galand, Magaly; Bland, Michael J; Mazel, Didier

    2012-01-01

    Although bacteria with multipartite genomes are prevalent, our knowledge of the mechanisms maintaining their genome is very limited, and much remains to be learned about the structural and functional interrelationships of multiple chromosomes. Owing to its bi-chromosomal genome architecture and its importance in public health, Vibrio cholerae, the causative agent of cholera, has become a preferred model to study bacteria with multipartite genomes. However, most in vivo studies in V. cholerae have been hampered by its genome architecture, as it is difficult to give phenotypes to a specific chromosome. This difficulty was surmounted using a unique and powerful strategy based on massive rearrangement of prokaryotic genomes. We developed a site-specific recombination-based engineering tool, which allows targeted, oriented, and reciprocal DNA exchanges. Using this genetic tool, we obtained a panel of V. cholerae mutants with various genome configurations: one with a single chromosome, one with two chromosomes of equal size, and one with both chromosomes controlled by identical origins. We used these synthetic strains to address several biological questions--the specific case of the essentiality of Dam methylation in V. cholerae and the general question concerning bacteria carrying circular chromosomes--by looking at the effect of chromosome size on topological issues. In this article, we show that Dam, RctB, and ParA2/ParB2 are strictly essential for chrII origin maintenance, and we formally demonstrate that the formation of chromosome dimers increases exponentially with chromosome size. PMID:22253612

  17. Strategy for assessing the technical, environmental, and engineering feasibility of subseabed disposal

    SciTech Connect

    Anderson, D.R.; Talbert, D.M.; Reese, D.; Boyer, D.G.; Herrmann, H.; Kelly, J.

    1980-07-01

    This report presents the strategy and management techniques used in the development of the US Subseabed Disposal Program (SDP) for possible disposal of both high-level waste and spent fuel. These have been developed through joint efforts of the Department of Energy (DOE), Division of Waste Isolation, the Sandia Technical Program Manager, the Technical Program Coordinators, the Advisory Group, and the Principal Investigators. Three subsections of this paper address the various components which make up the SDP strategy and management techniques. The first section summarizes the US DOE high-level waste and spent-fuel disposal program and the position that the SDP occupies within that program. The second section, the Subseabed Program Plan, addresses the technical and administrative tools which are employed to facilitate the day-to-day operation of the SDP. The third section addresses the current studies and future plans for addressing the legal, political, and international uncertainties that must be resolved before the SDP reaches the final engineering phases.

  18. Multi-lingual search engine to access PubMed monolingual subsets: a feasibility study.

    PubMed

    Darmoni, Stéfan J; Soualmia, Lina F; Griffon, Nicolas; Grosjean, Julien; Kerdelhué, Gaétan; Kergourlay, Ivan; Dahamna, Badisse

    2013-01-01

    PubMed contains many articles in languages other than English but it is difficult to find them using the English version of the Medical Subject Headings (MeSH) Thesaurus. The aim of this work is to propose a tool allowing access to a PubMed subset in one language, and to evaluate its performance. Translations of MeSH were enriched and gathered in the information system. PubMed subsets in main European languages were also added in our database, using a dedicated parser. The CISMeF generic semantic search engine was evaluated on the response time for simple queries. MeSH descriptors are currently available in 11 languages in the information system. All the 654,000 PubMed citations in French were integrated into CISMeF database. None of the response times exceed the threshold defined for usability (2 seconds). It is now possible to freely access biomedical literature in French using a tool in French; health professionals and lay people with a low English language may find it useful. It will be expended to several European languages: German, Spanish, Norwegian and Portuguese. PMID:23920740

  19. Genome Engineering in Vibrio cholerae: A Feasible Approach to Address Biological Issues

    PubMed Central

    Val, Marie-Eve; Skovgaard, Ole; Ducos-Galand, Magaly; Bland, Michael J.; Mazel, Didier

    2012-01-01

    Although bacteria with multipartite genomes are prevalent, our knowledge of the mechanisms maintaining their genome is very limited, and much remains to be learned about the structural and functional interrelationships of multiple chromosomes. Owing to its bi-chromosomal genome architecture and its importance in public health, Vibrio cholerae, the causative agent of cholera, has become a preferred model to study bacteria with multipartite genomes. However, most in vivo studies in V. cholerae have been hampered by its genome architecture, as it is difficult to give phenotypes to a specific chromosome. This difficulty was surmounted using a unique and powerful strategy based on massive rearrangement of prokaryotic genomes. We developed a site-specific recombination-based engineering tool, which allows targeted, oriented, and reciprocal DNA exchanges. Using this genetic tool, we obtained a panel of V. cholerae mutants with various genome configurations: one with a single chromosome, one with two chromosomes of equal size, and one with both chromosomes controlled by identical origins. We used these synthetic strains to address several biological questions—the specific case of the essentiality of Dam methylation in V. cholerae and the general question concerning bacteria carrying circular chromosomes—by looking at the effect of chromosome size on topological issues. In this article, we show that Dam, RctB, and ParA2/ParB2 are strictly essential for chrII origin maintenance, and we formally demonstrate that the formation of chromosome dimers increases exponentially with chromosome size. PMID:22253612

  20. Learning Lessons from Estuaries

    ERIC Educational Resources Information Center

    Schnittka, Christine

    2006-01-01

    There is something that draws all people to the sea and especially to the fertile estuaries that nuzzle up to its shores. An estuary serves as both a nursery and a grave for sea creatures. If life evolved from some primordial sea, it may well have been an estuary--a place where ocean and rivers meet and fresh and salty waters mingle in the

  1. Learning Lessons from Estuaries

    ERIC Educational Resources Information Center

    Schnittka, Christine

    2006-01-01

    There is something that draws all people to the sea and especially to the fertile estuaries that nuzzle up to its shores. An estuary serves as both a nursery and a grave for sea creatures. If life evolved from some primordial sea, it may well have been an estuary--a place where ocean and rivers meet and fresh and salty waters mingle in the…

  2. Feasibility of Conducting J-2X Engine Testing at the Glenn Research Center Plum Brook Station B-2 Facility

    NASA Technical Reports Server (NTRS)

    Schafer, Charles F.; Cheston, Derrick J.; Worlund, Armis L.; Brown, James R.; Hooper, William G.; Monk, Jan C.; Winstead, Thomas W.

    2008-01-01

    A trade study of the feasibility of conducting J-2X testing in the Glenn Research Center (GRC) Plum Brook Station (PBS) B-2 facility was initiated in May 2006 with results available in October 2006. The Propulsion Test Integration Group (PTIG) led the study with support from Marshall Space Flight Center (MSFC) and Jacobs Sverdrup Engineering. The primary focus of the trade study was on facility design concepts and their capability to satisfy the J-2X altitude simulation test requirements. The propulsion systems tested in the B-2 facility were in the 30,000-pound (30K) thrust class. The J-2X thrust is approximately 10 times larger. Therefore, concepts significantly different from the current configuration are necessary for the diffuser, spray chamber subsystems, and cooling water. Steam exhaust condensation in the spray chamber is judged to be the key risk consideration relative to acceptable spray chamber pressure. Further assessment via computational fluid dynamics (CFD) and other simulation capabilities (e.g. methodology for anchoring predictions with actual test data and subscale testing to support investigation.

  3. Estuary Data Mapper

    EPA Science Inventory

    The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary has three elements: an estuarine geo-referenced relational database, watershed GIS coverages, and tools to support decision-making. To facilita...

  4. DYNAMIC ESTUARY MODEL PERFORMANCE

    EPA Science Inventory

    Applications of the Dynamic Estuary Model (DEM) to both the Delaware and Potomac Estuaries by the Environmental Protection Agency during the 1970s are summarized and evaluated. Methods for calibrating, refining, and validating this model, and statistics for evaluating its perform...

  5. Feasibility study of using the RoboEarth cloud engine for rapid mapping and tracking with small unmanned aerial systems

    NASA Astrophysics Data System (ADS)

    Li-Chee-Ming, J.; Armenakis, C.

    2014-11-01

    This paper presents the ongoing development of a small unmanned aerial mapping system (sUAMS) that in the future will track its trajectory and perform 3D mapping in near-real time. As both mapping and tracking algorithms require powerful computational capabilities and large data storage facilities, we propose to use the RoboEarth Cloud Engine (RCE) to offload heavy computation and store data to secure computing environments in the cloud. While the RCE's capabilities have been demonstrated with terrestrial robots in indoor environments, this paper explores the feasibility of using the RCE in mapping and tracking applications in outdoor environments by small UAMS. The experiments presented in this work assess the data processing strategies and evaluate the attainable tracking and mapping accuracies using the data obtained by the sUAMS. Testing was performed with an Aeryon Scout quadcopter. It flew over York University, up to approximately 40 metres above the ground. The quadcopter was equipped with a single-frequency GPS receiver providing positioning to about 3 meter accuracies, an AHRS (Attitude and Heading Reference System) estimating the attitude to about 3 degrees, and an FPV (First Person Viewing) camera. Video images captured from the onboard camera were processed using VisualSFM and SURE, which are being reformed as an Application-as-a-Service via the RCE. The 3D virtual building model of York University was used as a known environment to georeference the point cloud generated from the sUAMS' sensor data. The estimated position and orientation parameters of the video camera show increases in accuracy when compared to the sUAMS' autopilot solution, derived from the onboard GPS and AHRS. The paper presents the proposed approach and the results, along with their accuracies.

  6. Prediction in ungauged estuaries: An integrated theory

    NASA Astrophysics Data System (ADS)

    Savenije, Hubert H. G.

    2015-04-01

    Many estuaries in the world are ungauged. The International Association of Hydrological Sciences completed its science decade on Prediction in Ungauged Basins (PUB) in 2012 (Hrachowitz et al.). Prediction on the basis of limited data is a challenge in hydrology, but not less so in estuaries, where data on fundamental processes are often lacking. In this paper, relatively simple, but science-based, methods are presented that allow researchers, engineers, and water managers to obtain first-order estimates of essential process parameters in estuaries, such as the estuary depth, the tidal amplitude, the tidal excursion, the phase lag, and the salt water intrusion, on the basis of readily obtainable information, such as topographical maps and tidal tables. These apparently simple relationships are assumed to result from the capacity of freely erodible water bodies to adjust themselves to external drivers and to dissipate the free energy from these drivers as efficiently as possible. Thus, it is assumed that these systems operate close to their thermodynamic limit, resulting in predictable patterns that can be described by relatively simple equations. Although still much has to be done to develop an overall physics-based theory, this does not prevent us from making use of the empirical "laws" that we observe in alluvial estuaries.

  7. Feasibility study of a pressure-fed engine for a water recoverable space shuttle booster. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The activities leading to a tentative concept selection for a pressure-fed engine and propulsion support are outlined. Multiple engine concepts were evaluted through parallel engine major component and system analyses. Booster vehicle coordination, tradeoffs, and technology/development aspects are included. The concept selected for further evaluation has a regeneratively cooled combustion chamber and nozzle in conjuction with an impinging element injector. The propellants chosen are LOX/RP-1, and combustion stabilizing baffles are used to assure dynamic combustion stability.

  8. Engineering and economic feasibility of using poultry litter as a fuel to generate electric power at Maryland`s Eastern Correctional Institute

    SciTech Connect

    Estomin, S.L.; Walters, G.; Prasad, A.; Ross, J.

    1998-02-16

    This report presents an analysis of the engineering, environmental, and economic feasibility of the Eastern Correctional Institute (ECI) meeting its electric power and thermal requirements by relying on poultry litter as a fuel. In addition to satisfying all or a portion of the utility requirements of ECI, a maximum/medium security prison located in Princess Anne, Maryland, the use of poultry litter as a fuel would reduce the amount of poultry waste currently used on the Eastern Shore as fertilizer. Based on the engineering and environmental assessments conducted, three alternative scenarios to satisfy ECI`s electric power supply and thermal requirements using poutlry litter as a fuel were developed. For all scenarios, as well as a base case defined by current operations at ECI, 20-year life-cycle costs were estimated based on projections of usage, capital costs, fuel costs, labor costs, and other relevant factors.

  9. Visualizing feasible operating ranges within tissue engineering systems using a "windows of operation" approach: a perfusion-scaffold bioreactor case study.

    PubMed

    McCoy, Ryan J; O'Brien, Fergal J

    2012-12-01

    Tissue engineering approaches to developing functional substitutes are often highly complex, multivariate systems where many aspects of the biomaterials, bio-regulatory factors or cell sources may be controlled in an effort to enhance tissue formation. Furthermore, success is based on multiple performance criteria reflecting both the quantity and quality of the tissue produced. Managing the trade-offs between different performance criteria is a challenge. A "windows of operation" tool that graphically represents feasible operating spaces to achieve user-defined levels of performance has previously been described by researchers in the bio-processing industry. This paper demonstrates the value of "windows of operation" to the tissue engineering field using a perfusion-scaffold bioreactor system as a case study. In our laboratory, perfusion bioreactor systems are utilized in the context of bone tissue engineering to enhance the osteogenic differentiation of cell-seeded scaffolds. A key challenge of such perfusion bioreactor systems is to maximize the induction of osteogenesis but minimize cell detachment from the scaffold. Two key operating variables that influence these performance criteria are the mean scaffold pore size and flow-rate. Using cyclooxygenase-2 and osteopontin gene expression levels as surrogate indicators of osteogenesis, we employed the "windows of operation" methodology to rapidly identify feasible operating ranges for the mean scaffold pore size and flow-rate that achieved user-defined levels of performance for cell detachment and differentiation. Incorporation of such tools into the tissue engineer's armory will hopefully yield a greater understanding of the highly complex systems used and help aid decision making in future translation of products from the bench top to the market place. PMID:22627891

  10. A feasibility study of dynamic stress analysis inside a running internal combustion engine using synchrotron X-ray beams.

    PubMed

    Baimpas, Nikolaos; Drakopoulos, Michael; Connolley, Thomas; Song, Xu; Pandazaras, Costas; Korsunsky, Alexander M

    2013-03-01

    The present investigation establishes the feasibility of using synchrotron-generated X-ray beams for time-resolved in situ imaging and diffraction of the interior components of an internal combustion engine during its operation. The demonstration experiment was carried out on beamline I12 (JEEP) at Diamond Light Source, UK. The external hutch of the JEEP instrument is a large-scale engineering test bed for complex in situ processing and simulation experiments. The hutch incorporates a large capacity translation and rotation table and a selection of detectors for monochromatic and white-beam diffraction and imaging. These capabilities were used to record X-ray movies of a motorcycle internal combustion engine running at 1850 r.p.m. and to measure strain inside the connecting rod via stroboscopic X-ray diffraction measurement. The high penetrating ability and high flux of the X-ray beam at JEEP allowed the observation of inlet and outlet valve motion, as well as that of the piston, connecting rod and the timing chain within the engine. Finally, the dynamic internal strain within the moving connecting rod was evaluated with an accuracy of ~50 × 10(-6). PMID:23412489

  11. DELAWARE ESTUARY PCB MODEL

    EPA Science Inventory

    The Delaware River Basin Commission recently completed the first phase of a program to develop and implement Total Maximum Daily Loads (TMDLs) for toxic pollutants for the Delaware Estuary. This complex body of water extends from the head of tide at Trenton, NJ (River Mile 133.2...

  12. DC-9/JT8D refan, Phase 1. [technical and economic feasibility of retrofitting DC-9 aircraft with refan engine to achieve desired acoustic levels

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Analyses and design studies were conducted on the technical and economic feasibility of installing the JT8D-109 refan engine on the DC-9 aircraft. Design criteria included minimum change to the airframe to achieve desired acoustic levels. Several acoustic configurations were studied with two selected for detailed investigations. The minimum selected acoustic treatment configuration results in an estimated aircraft weight increase of 608 kg (1,342 lb) and the maximum selected acoustic treatment configuration results in an estimated aircraft weight increase of 809 kg (1,784 lb). The range loss for the minimum and maximum selected acoustic treatment configurations based on long range cruise at 10 668 m (35,000 ft) altitude with a typical payload of 6 804 kg (15,000 lb) amounts to 54 km (86 n. mi.) respectively. Estimated reduction in EPNL's for minimum selected treatment show 8 EPNdB at approach, 12 EPNdB for takeoff with power cutback, 15 EPNdB for takeoff without power cutback and 12 EPNdB for sideline using FAR Part 36. Little difference was estimated in EPNL between minimum and maximum treatments due to reduced performance of maximum treatment. No major technical problems were encountered in the study. The refan concept for the DC-9 appears technically feasible and economically viable at approximately $1,000,000 per airplane. An additional study of the installation of JT3D-9 refan engine on the DC-8-50/61 and DC-8-62/63 aircraft is included. Three levels of acoustic treatment were suggested for DC-8-50/61 and two levels for DC-8-62/63. Results indicate the DC-8 technically can be retrofitted with refan engines for approximately $2,500,000 per airplane.

  13. Feasibility study of air-breathing turbo-engines for horizontal take-off and landing space plane

    SciTech Connect

    Minoda, M.; Sakata, K.; Tamaki, T.; Saitoh, T.; Yasuda, A.

    1989-01-01

    Various concepts of air-breathing engines (ABEs) that could be used for a horizontal take-off and landing SSTO vehicle are investigated. The performances (with respect to thrust and the specific fuel consumption) of turboengines based on various technologies, including a turbojet with and without afterburner (TJ), turboramjet, and air-turbo-ram jet engines are compared. The mission capabilities of these ABEs for SSTO and TSTO vehicles is examined in terms of the ratio of the effective remaining weight (i.e., the weight on the orbit) to the take-off gross weight, using two-dimensional flight analysis. It was found that the dry TJ with the turbine inlet temperature 2000 C is one of the most promising candidates for the propulsion system of the SSTO vehicle, because of its small weight and high specific impulse. 6 refs.

  14. Evaluation of feasibility of measuring EHD film thickness associated with cryogenic fluids. [for space shuttle main engine bearings

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Merriman, T. L.; Stockwell, R. D.; Dufrane, K. F.

    1983-01-01

    The feasibility of measuring elastohydrodynamic (EHD) films as formed with a cryogenic (LN2) fluid is evaluated. Modifications were made to an existing twin disk EHD apparatus to allow for disk lubrication with liquid nitrogen. This disk apparatus is equipped with an X-ray system for measuring the thickness of any lubricant film that is formed between the disks. Several film thickness experiments were conducted with the apparatus which indicate that good lubrication films are filmed with LN2. In addition to the film thickness studies, failure analyses of three bearings were conducted. The HPOTP turbine end bearings had experienced axial loads of 36,000 to 44,000 N (8,000 to 10,000 lb). High continuous radial loads were also experienced, which were most likely caused by thermal growth of the inner race. The resulting high internal loads caused race spalling and ball wear to occur.

  15. Feasibility study on oil droplet flow investigations inside aero engine bearing chambers -- PDPA techniques in combination with numerical approaches

    SciTech Connect

    Glahn, A.; Kurreck, M.; Willmann, M.; Wittig, S.

    1996-10-01

    The present paper deals with oil droplet flow phenomena in aero engine bearing chambers. An experimental investigation of droplet sizes and velocities utilizing a Phase Doppler Particle Analyzer (PDPA) has been performed for the first time in bearing chamber atmospheres under real engine conditions. Influences of high rotational speeds are discussed for individual droplet size classes. Although this is an important contribution to a better understanding of the droplet flow impact on secondary air/oil system performance, an analysis of the droplet flow behavior requires an incorporation of numerical methods because detailed measurements as performed here suffer from both strong spatial limitations with respect to the optical accessibility in real engine applications and constraints due to the extremely time-consuming nature of an experimental flow field analysis. Therefore, further analysis is based on numerical methods. Droplets characterized within the experiments are exposed to the flow field of the gaseous phase predicted by use of the well-known CFD code EPOS. The droplet trajectories and velocities are calculated within a Lagrangian frame of reference by forward numerical integration of the particle momentum equation. This paper has been initiated rather to show a successful method of bearing chamber droplet flow analysis by a combination of droplet sizing techniques and numerical approaches than to present field values as a function of all operating parameters. However, a first insight into the complex droplet flow phenomena is given and specific problems in bearing chamber heat transfer are related to the droplet flow.

  16. THE IMPACTS OF UPOGEBIA PUGETTENSIS POPULATIONS ON ORGANIC MATTER AND NUTRIENT CYCLING IN PACIFIC NORTHWEST ESTUARIES

    EPA Science Inventory

    The burrowing thalassinid shrimp, Upogebia pugettensis, is a major ecosystem engineering species of Pacific estuaries and can structure the physical, chemical, and biotic properties of benthic habitats. This study utilized incubations, benthic chambers and porewater peepers to q...

  17. Ecology of estuaries

    SciTech Connect

    Kennish, M.J. )

    1992-01-01

    Ecology of Estuaries: Anthropogenic Effects represents the most definitive and comprehensive source of reference information available on the human impact on estuarine ecosystems. The book discusses both acute and insidious pollution problems plaguing these coastal ecotones. It also provides a detailed examination of the deleterious and pervasive effects of human activities on biotic communities and sensitive habitat areas in estuaries. Specific areas covered include organic loading, oil pollution, polynuclear aromatic hydrocarbons, chlorinated hydrocarbons, heavy metals, dredging and dredge-spoil disposal, radionuclides, as well as other contaminants and processes. The diverse components of these anthropogenic influences are assembled in an organized framework and presented in a clear and concise style that will facilitate their understanding.

  18. Early Feasibility Testing and Engineering Development of a Sutureless Beating Heart (SBH) Connector for Left Ventricular Assist Devices (LVAD)

    PubMed Central

    Koenig, Steven C; Jimenez, Jorge H; West, Seth D; Sobieski, Michael A; Choi, Young; Monreal, Gretel; Giridharan, Guruprasad A; Soucy, Kevin G; Slaughter, Mark S

    2014-01-01

    APK Advanced Medical Technologies (Atlanta, GA) is developing a sutureless beating heart (SBH) left ventricular assist device (LVAD) connector system consisting of anchoring titanium coil, titanium cannula with integrated silicone hemostatic valve, coring and delivery tool, and LVAD locking mechanism to facilitate LVAD inflow surgical procedures. Feasibility testing was completed in human cadavers (n=4) under simulated normal and hypertensive conditions using saline to observe seal quality in degraded human tissue and assess anatomic fit; acutely in ischemic heart failure (IHF) bovine model (n=2) to investigate short-term performance and ease of use; and chronically for 30-days in healthy calves (n=2) implanted with HeartWare HVAD to evaluate performance and biocompatibility. Complete hemostasis was achieved in human cadavers and animals at LV pressures up to 170 mmHg. In animals, off pump (no cardiopulmonary bypass) anchoring of the connector was accomplished in less than 1 minute with no residual bleeding after full delivery and locking of the LVAD; and implant of connector and LVAD were successfully completed in under 10 minutes with total procedure blood loss less than 100mL. In chronic animals prior to necropsy, no signs of leakage or disruption at the attachment site were observed at systolic LV pressures >200 mmHg. PMID:25238500

  19. Early feasibility testing and engineering development of a sutureless beating heart connector for left ventricular assist devices.

    PubMed

    Koenig, Steven C; Jimenez, Jorge H; West, Seth D; Sobieski, Michael A; Choi, Young; Monreal, Gretel; Giridharan, Guruprasad A; Soucy, Kevin G; Slaughter, Mark S

    2014-01-01

    APK Advanced Medical Technologies (Atlanta, GA) is developing a sutureless beating heart (SBH) left ventricular assist device (LVAD) connector system consisting of anchoring titanium coil, titanium cannula with integrated silicone hemostatic valve, coring and delivery tool, and LVAD locking mechanism to facilitate LVAD inflow surgical procedures. Feasibility testing was completed in human cadavers (n = 4) under simulated normal and hypertensive conditions using saline to observe seal quality in degraded human tissue and assess anatomic fit; acutely in ischemic heart failure bovine model (n = 2) to investigate short-term performance and ease of use; and chronically for 30 days in healthy calves (n = 2) implanted with HeartWare HVAD to evaluate performance and biocompatibility. Complete hemostasis was achieved in human cadavers and animals at LV pressures up to 170 mm Hg. In animals, off-pump (no cardiopulmonary bypass) anchoring of the connector was accomplished in less than 1 minute with no residual bleeding after full delivery and locking of the LVAD; and implant of connector and LVAD were successfully completed in under 10 minutes with total procedure blood loss less than 100 ml. In chronic animals before necropsy, no signs of leakage or disruption at the attachment site were observed at systolic LV pressures >200 mm Hg. PMID:25238500

  20. Early Feasibility Testing and Engineering Development of the Transapical Approach for the HeartWare MVAD Ventricular Assist System

    PubMed Central

    Tamez, Daniel; LaRose, Jeffrey A.; Shambaugh, Charles; Chorpenning, Katherine; Soucy, Kevin G; Sobieski, Michael A; Sherwood, Leslie; Giridharan, Guruprasad A; Monreal, Gretel; Koenig, Steven C; Slaughter, Mark S

    2014-01-01

    Implantation of ventricular assist devices (VADs) for treatment of end-stage heart failure (HF) falls decidedly short of clinical demand, which exceeds 100,000 HF patients per year. VAD implantation often requires major surgical intervention with associated risk of adverse events and long recovery periods. To address these limitations, HeartWare, Inc. (Miami Lakes, FL) has developed a platform of miniature ventricular devices with progressively reduced surgical invasiveness and innovative patient peripherals. One surgical implant concept is a transapical version of the miniaturized left ventricular assist device (MVAD). The HeartWare MVAD Pump is a small, continuous flow, full-support device that has a displacement volume of 22mL. A new cannula configuration has been developed for transapical implantation, where the outflow cannula is positioned across the aortic valve. The two primary objectives for this feasibility study were to evaluate anatomic fit and surgical approach and efficacy of the transapical MVAD configuration. Anatomic fit and surgical approach were demonstrated using human cadavers (n=4). Efficacy was demonstrated in acute (n =2) and chronic (n = 1) bovine model experiments and assessed by improvements in hemodynamics, biocompatibility, flow dynamics, and histopathology. Potential advantages of the MVAD Pump include flow support in the same direction as the native ventricle, elimination of cardiopulmonary bypass, and minimally-invasive implantation. PMID:24399057

  1. Ecology of estuaries

    SciTech Connect

    Kennish, M.J.

    1986-01-01

    This book is a summary of information available on estuarine ecology, that reviews concepts and problems of estuaries and assesses the value of these coastal systems. It investigates such topics as water circulation and mixing, trace elements, nutrients, organic matter, and sedimentary processes, with reviews on more than two decades of intense study. Chapters reflect contributions from a variety of interdisciplinary sciences including botany, chemistry, ecology, geology, physics, and zoology.

  2. Burrowing shrimp as foundation species in NE Pacific estuaries

    EPA Science Inventory

    My talk will be about the my research to characterize the role that burrowing shrimp play as foundation/engineering species in Pacific NW estuaries. My research has focused on measuring the abundance & distribution of two species (ghost shrimp & mud shrimp) at ecosystem scales, ...

  3. Feasibility of non-invasive detection of engineered nanoparticles in food mimicking matrices by Optical Coherence Tomography.

    PubMed

    Grombe, Ringo; Kirsten, Lars; Mehner, Mirko; Linsinger, Thomas P J; Emons, Hendrik; Koch, Edmund

    2014-06-15

    The study was dedicated towards the detection of Engineered Nanoparticles (ENPs) by means of Optical Coherence Tomography (OCT). Polymeric films were produced to mimic complex food matrices whereas gold nanorods (AuNRs) were embedded to act as ENPs. The straightforward coating application resulted in a sufficient film wetting, adhesion and homogenous AuNR distribution. Compared to food samples, these films are simpler and better defined. Such artefacts are therefore promising candidate materials for quality assurance and regulatory matters. The OCT investigations revealed a dependency of the measured signal intensity on the AuNR concentration in the film. The limit of detection for the setup and material was estimated to be -8 dB. This value corresponds to a ppm nanoparticle concentration being well below the concentration used in food additive applications. Thus, the findings indicate the potential of OCT to screen food/feed products for a number of ENPs. PMID:24491752

  4. Transient silencing of the KASII genes is feasible in Nicotiana benthamiana for metabolic engineering of wax ester composition

    PubMed Central

    Aslan, Selcuk; Hofvander, Per; Dutta, Paresh; Sitbon, Folke; Sun, Chuanxin

    2015-01-01

    The beta-ketoacyl-ACP synthase II (KASII) is an enzyme in fatty acid biosynthesis, catalyzing the elongation of 16:0-acyl carrier protein (ACP) to 18:0-ACP in plastids. Mutations in KASII genes in higher plants can lead to lethality, which makes it difficult to utilize the gene for lipid metabolic engineering. We demonstrated previously that transient expression of plastid-directed fatty acyl reductases and wax ester synthases could result in different compositions of wax esters. We hypothesized that changing the ratio between C16 (palmitoyl-compounds) and C18 (stearoyl-compounds) in the plastidic acyl-ACP pool by inhibition of KASII expression would change the yield and composition of wax esters via substrate preference of the introduced enzymes. Here, we report that transient inhibition of KASII expression by three different RNAi constructs in leaves of N. benthamiana results in almost complete inhibition of KASII expression. The transient RNAi approach led to a shift of carbon flux from a pool of C18 fatty acids to C16, which significantly increased wax ester production in AtFAR6-containing combinations. The results demonstrate that transient inhibition of KASII in vegetative tissues of higher plants enables metabolic studies towards industrial production of lipids such as wax esters with specific quality and composition. PMID:26063537

  5. Feasibility and limitations of the round robin test for assessment of in vitro chondrogenesis evaluation protocol in a tissue-engineered medical product.

    PubMed

    Yokoi, Masako; Hattori, Koji; Narikawa, Koichi; Ohgushi, Hajime; Tadokoro, Mika; Hoshi, Kazuto; Takato, Tsuyoshi; Myoui, Akira; Nanno, Katsuhiko; Kato, Yukio; Kanawa, Masami; Sugawara, Katsura; Kobo, Tomoko; Ushida, Takashi

    2012-07-01

    Tissue-engineered medical products (TEMPs) should be evaluated before implantation. Therefore, it is indispensable to establish evaluation protocols in regenerative medicine. Whether or not such evaluation protocols are reasonable is generally verified through a 'round robin' test. However, the round robin test for TEMPs intrinsically includes a deficiency, because 'identical' specimens can not be prepared for TEMPs. The aim of the study was to assess the feasibility and limitations of the round robin test for TEMPs by using a prepared evaluation protocol. We adopted tissue-engineered cartilage constructs as delivered specimens and a protocol of measuring sGAG content as an evaluation protocol proposed to ISO TC150/SC7, which is an invasive, but usually applied, method, although non-invasive methods are keenly required in evaluating TEMPs. The results showed that: (a) the coefficient of variation (CV) of the measured sGAG contents in intralaboratory tests was ~5% at most; (b) the CV of sGAG content in the scheme where each participating laboratory measured different constructs was comparable with that in the scheme where each participating laboratory measured one half of a construct along with the organizing laboratory; (c) the CV caused by factors other than the specimen was ~15%, comparable to that in reproducible experiments in biomedical fields. Based on these results, the study concludes that a round robin test for a TEMP could be valuable, under the condition that the delivered TEMPs are sufficiently reproducible so that the CV of the measured values is?

  6. Delaware Estuary situation reports. Emergency response: How do emergency management officials address disasters in the Delaware Estuary

    SciTech Connect

    Sylves, R.T.

    1991-01-01

    From hurricanes and other natural threats to oil spills and other manmade emergencies, the Delaware Estuary has experienced a variety of disasters over the years. The toll that these events take on the estuary and those who live on its shores depends largely upon the degree of emergency preparedness, speed of response, and effectiveness of recovery operations. In Emergency Response: How Do Emergency Management Officials Address Disasters in the Delaware Estuary, the latest addition to its Delaware Estuary Situation Report series, the University of Delaware Sea Grant College Program defines emergency management; examines the roles that the Coast Guard, Army Corps of Engineers, and Environmental Protection Agency play in an emergency; and reviews how each of these federal agencies operated during an actual disaster--the 1985 Grand Eagle oil spill. The report was written by Dr. Richard T. Sylves, a professor of political science at the University of Delaware. Sylves has been studying emergency management for the past 15 years, with special emphasis on oil spill preparedness and response in the Mid-Atlantic Region. The Delaware Estuary Situation Report is 12 pages long and contains maps and photographs, as well as a detailed account of response and recovery operations undertaken during the Grand Eagle oil spill. A comparison of the 1985 Grand Eagle spill and the 1989 Presidente Rivera spill also is included.

  7. Technical and Engineering Feasibility Study of the Vitrification of Plutonium-Bearing Sludges at the Krasnoyarsk Mining and Chemical Combine by Means of Microwave Heating

    SciTech Connect

    Revenko, Y.A.; Kudinov, K.G.; Tretyakov, A.A.; Vassilyev, A.V.; Borisov, G.B.; Nazarov, A.V.; Aloy, A.S.; Shvedov, A.A.; Gusakov, B.V.; Jardine, L.J.

    2000-03-03

    This engineering feasibility study compared three possible technical options and their economic viability of processing plutonium-bearing sludges containing 0.6 MT of weapons-grade Pu accumulated at the Mining and Chemical Combine (MCC) at Krasnoyarsk. In Option 1, the baseline, the sludges are processed by extraction and purification of plutonium for storage using existing technologies, and the non-soluble radioactive residues generated in these processes undergo subsequent solidification by cementation. Options 2 and 3 involve the direct immobilization of plutonium-bearing sludges into a solid matrix (without any Pu extraction) using a microwave solidification process in a metal crucible to produce a glass, which is boron-silicate in Option 2 and phosphate glass in Option 3. In all three options, the solid radioactive waste end products will be placed in storage for eventual geologic disposal. Immobilization of residual plutonium into glass-like matrices provides both safer storage over the lifetime of the radionuclides and greater security against unauthorized access to stored materials than does the extraction and concentration of PuO{sub 2}, supporting our efforts toward non-proliferation of fissile materials. Although immobilization in boron-silicate glass appears now to be marginally preferable compared to the phosphate glass option, a number of technical issues remain to be assessed by further study to determine the preferable immobilization option.

  8. SSPA Equipment Engineering Feasibility Report

    SciTech Connect

    N.E. Woolstenhulme; C.R. Clark

    2011-09-01

    In response to a demanding reactor conversion schedule, construction of the Shielded Sample Preparation Area (SSPA) was initiated in 2010 to augment the existing capabilities of the Hot Fuel Examination Facility (HFEF). While HFEF is and will remain the workhorse for post irradiation sample preparation, there is currently a large backlog of Post-Irradiation Examination (PIE) experiments caused by numerous competing projects (this backlog is expected to continue for the foreseeable future). HFEF, in its present configuration also lacks the ability to prepare samples suitable for several of the tests that have been identified for the successful conclusion of the RERTR program; these samples require fine detail machining of irradiated fuel plates.

  9. Dissolved oxygen in two Oregon estuaries: Importance of the ocean-estuary connection

    EPA Science Inventory

    We examined the role of the ocean estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

  10. Dissolved oxygen in two Oregon estuaries: Importance of the ocean-estuary connection - March 2011

    EPA Science Inventory

    We examined the role of the oceanestuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO w...

  11. Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection

    EPA Science Inventory

    We examined the role of the ocean estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

  12. Stream, lake, estuary, and ocean pollution, 2nd edition

    SciTech Connect

    Nemerow, N.L.

    1991-01-01

    This book, an updated version of the 1985 edition, contains thirteen chapters, beginning with a preface which provides the objective of the book. The primary objective is to offer a comprehensive survey of the biological, hydrological, mathematical, and biochemical aspects of stream, lake, estuary, and ocean pollution analysis. The book also contains ten appendices of useful tables and nomographs of pertinent data. This book provides a very good summary and review of stream, lake, estuary, and ocean pollution. This book is recommended for environmental engineering students, environmental consulting engineers, and regulatory personnel. It provides an excellent summary of the field of stream and lake analysis and modeling. Every chapter includes a significant number of questions and pertinent references.

  13. PECONIC ESTUARY EELGRASS HABITAT CRITERIA STUDY

    EPA Science Inventory

    PECONIC ESTUARY EELGRASS HABITAT CRITERIA STUDY The main objective of this study is to develop criteria for eelgrass habitat establishment and persistence within the Peconic Estuary utilizing various environmental analyses. The Program evaluated water and sediment quality data to...

  14. EXHIBIT OF EMPACT ESTUARY MONITORING HANDBOOKS

    EPA Science Inventory

    Related EMPACT documents were displayed at the National Estuary Day Celebration held in Washington, DC, September 30-Octuber 4, 2002. The estuary monitoring technology transfer handbooks displayed were prepared based on information and monitoring technologies developed from selec...

  15. KNOW YOUR ESTUARY: THE WATER THROUGH TIME

    EPA Science Inventory

    This presentation will focus on historical changes in water quality in the Yaquina Estuary, Oregon, and factors which influence water quality within this estuary. Topics presented will include the importance of ocean conditions on water quality in the estuary; historical changes...

  16. PECONIC ESTUARY STORMWATER ASSESSMENT AND PLANNING TOOL

    EPA Science Inventory

    PECONIC ESTUARY STORMWATER ASSESSMENT AND PLANNING TOOL Horsley & Witten, Inc. was contracted by the Peconic Estuary Program to create a Regional Stormwater Runoff Management Plan designed to mitigate loadings of fecal coliform bacteria and nitrogen to the Peconic Estuary. The pu...

  17. MACROINVERTEBRATE PROTOCOLS ON ESTUARIES IN NEW JERSEY

    EPA Science Inventory

    Estuaries of the Atlantic coastal New Jersey extend from Newark Bay southward to Cape May Inlet. The rich diversities of habitats found in these estuaries provide important nursery areas for fish and marine invertebrates. Federal and state agencies routinely monitor estuaries fo...

  18. Feasibility study of an Integrated Program for Aerospace-vehicle Design (IPAD) system. Volume 3: Engineering creative/evaluation processes, phase 1, task 2

    NASA Technical Reports Server (NTRS)

    Garrocq, C. A.; Hosek, J. J.

    1973-01-01

    A series of functional flow charts are considered that were developed to properly identify and record the degree of participation of the disciplines considered in this feasibility study and the type of data required in the design process.

  19. Ecology of estuaries: Anthropogenic effects

    SciTech Connect

    Kennish, M.J.

    1992-01-01

    Estuaries and near-shore oceanic water are subjected to a multitude of human wastes. The principal objective of this book is to examine anthropogenic effects on estuaries, and it focuses primarily on contaminants in coastal systems. Covered within various chapters are the following topics: waste disposal strategies; definition and classification of pollutants (including organic loading, oil pollution, polynuclear aromatic hydrocarbons; chlorinated hydrocarbons; heavy metals; radionuclides) biological impacts; waste management; impacts of power plants; dredging and spoil disposal; case studies, primarily Chesapeake Bay. The book serves as a text and as a reference.

  20. NTRE extended life feasibility assessment

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Results of a feasibility analysis of a long life, reusable nuclear thermal rocket engine are presented in text and graph form. Two engine/reactor concepts are addressed: the Particle Bed Reactor (PBR) design and the Commonwealth of Independent States (CIS) concept. Engine design, integration, reliability, and safety are addressed by various members of the NTRE team from Aerojet Propulsion Division, Energopool (Russia), and Babcock & Wilcox.

  1. Valuing environmental water pulses into the Incomati estuary: Key to achieving equitable and sustainable utilisation of transboundary waters

    NASA Astrophysics Data System (ADS)

    Sengo, D. José; Kachapila, Albert; Zaag, Pieter van der; Mul, Marloes; Nkomo, Sakhiwe

    Upstream developments in the Incomati river basin, shared by South Africa, Swaziland and Mozambique, have altered downstream flows significantly. The frequency of small floods into the estuary has been reduced dramatically. This change in the flow regime has impacted on the state of the environment downstream, and the Incomati estuary in particular. The estuary requires fresh water pulses that naturally occur, and the resulting seasonal flooding of the plains. Resource-poor rural households depend on the goods and services that the estuary and flood plains provide such as wood, charcoal, building materials, fish and shrimp, wetland farming, and tourism. Alteration of the flow regime into the estuary has a negative impact on the state of the environment and hence on the goods and services the estuary yields; a phenomenon the people living near the estuary are keenly aware of. The article estimates the value of the goods and services that the estuary currently provides, that is under the conditions of a changed flow regime. A linear relationship is then assumed between fresh water pulses into the estuary and the goods and services it provides, so that the order of magnitude of the economic value of fresh water pulses into the estuary may be approximated. Various development scenarios in the Incomati basin are then considered, that have different upstream and downstream impacts on water availability, and the basin-wide benefits and costs are compared. The paper concludes that the principle of sharing the benefits derived from the water resources, rather than the water itself, as proposed by authors such as [Sadoff, C.W., Grey, D., 2002. Beyond the river: the benefits of cooperation on international rivers. Water Policy 4, 389-403], may be a feasible approach only if the less tangible benefits and functions, especially those of the environment, are assigned an appropriate value and corresponding priority.

  2. DELAWARE ESTUARY A MANAGEMENT PLAN FOR THE DELAWARE ESTUARY

    EPA Science Inventory

    Wise conservation and management of the Delaware Estuary is arguably the most important cooperative environmental initiative ever jointly undertaken by the States of New Jersey, Pennsylvania, and Delaware. While much has been accomplished over the past few decades to improve wate...

  3. Estuary program primer. National Estuary Program. Draft report

    SciTech Connect

    Not Available

    1987-10-01

    The manual provides an overview of the National Estuary Program and its functions and management structure. The manual also describes the Comprehensive Conservation and Management Plan, a framework that can be used to help in prevention and control of pollution, land over-use, and man-environment conflicts.

  4. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring and Evaluation FY08 Annual Report.

    SciTech Connect

    Johnson, GE; Diefenderfer, HL

    2008-09-29

    The Estuary/Ocean Subgroup (EOS) is part of the research, monitoring, and evaluation (RME) effort that the Action Agencies (Bonneville Power Administration (BPA), U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In fiscal year 2008 (FY08), EOS project accomplishments included (1) subgroup meetings; (2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; (3) project management via BPA's project tracking system, Pisces; (4) quarterly project status reports; and (5) a major revision to the Estuary RME document and its subsequent regional release (new version January 2008). Many of the estuary RME recommendations in this document were incorporated into the Biological Opinion on FCRPS operations (May 2008). In summary, the FY08 EOS project resulted in expanded, substantive coordination with other regional RME forums, a new version of the federal Estuary RME program document, and implementation coordination. This annual report is a FY08 deliverable for the project titled Facilitation of the Estuary/Ocean Subgroup.

  5. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY08 Annual Report

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2008-09-29

    The Estuary/Ocean Subgroup (EOS) is part of the research, monitoring, and evaluation (RME) effort that the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In fiscal year 2008 (FY08), EOS project accomplishments included 1) subgroup meetings; 2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; 3) project management via the project tracking system, Pisces; 4) quarterly project status reports; and 5) a major revision to the Estuary RME document and its subsequent regional release (new version January 2008). Many of the estuary RME recommendations in this document were incorporated into the Biological Opinion on hydrosystem operations (May 2008). In summary, the FY08 EOS project resulted in expanded, substantive coordination with other regional RME forums, a new version of the federal Estuary RME program document, and implementation coordination. This annual report is a FY08 deliverable for the project titled Facilitation of the Estuary/Ocean Subgroup.

  6. Simulated Sampling of Estuary Plankton

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.; Jenkins, Deborah Bainer

    2009-01-01

    To find out about the microscopic life in the valuable estuary environment, it is usually necessary to be near the water. This dry lab offers an alternative, using authentic data and a simulation of plankton sampling. From the types of organisms found in the sample, middle school students can infer relationships in the biological and physical

  7. LAKE PONTCHARTRAIN ESTUARY CONSERVATION PLAN

    EPA Science Inventory

    The Nature Conservancy will conduct a series of a least four science expert workshops to develop a Site Conservation Plan for the Lake Pontchartrain Estuary and adjacent wetlands. The objective of the Site Conservation Plan is to identify conservation targets, threats or stresse...

  8. Food Webs in an Estuary.

    ERIC Educational Resources Information Center

    Dunne, Barbara B.

    The Maryland Marine Science Education Project has produced a series of mini-units in marine science education for the junior high/middle school classroom. This unit focuses on food chains in an estuary. Although the unit specifically treats the Chesapeake Bay, it may be adapted for use with similar estuarine systems. In addition, the unit may be…

  9. Simulated Sampling of Estuary Plankton

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.; Jenkins, Deborah Bainer

    2009-01-01

    To find out about the microscopic life in the valuable estuary environment, it is usually necessary to be near the water. This dry lab offers an alternative, using authentic data and a simulation of plankton sampling. From the types of organisms found in the sample, middle school students can infer relationships in the biological and physical…

  10. New Bedford Harbor Superfund Project, Acushnet River estuary engineering feasibility study of dredging and dredged material disposal alternatives. Report 4. Surface runoff quality evaluation for confined disposal. Technical report, June-February 1987

    SciTech Connect

    Skogerboe, J.G.; Price, R.A.; Brandon, D.L.

    1988-10-01

    The thickness of capping material needed to chemically sequests the polychlorinated biphenyl (PCB)-contaminated New Bedford Harbor sediment from the overlying water column and aquatic biota was assessed in a small-scale predictive test. Changes in the overlying water concentrations of dissolved oxygen, ammonium-nitrogen, and orthophosphate-phosphorus were monitored following isolation of the water column from the atmosphere by placing a 4-cm layer of mineral oil on the water surface. The chemical tracers (ammonium-nitrogen and orthophosphate-phosphorus) were selected for their mobility under anaerobic conditions, ease of measurement, and generally high concentrations in contaminated dredged material compared with clean sediments. The chemical tracers were used to evaluate the efficiency of the capping material in preventing transfer of contaminants from New Bedford Harbor sediment into the overlying water column.

  11. The Need for Definitions in Understanding Estuaries

    NASA Astrophysics Data System (ADS)

    Elliott, M.; McLusky, D. S.

    2002-12-01

    This paper considers what the definition/classification of estuaries has taught us and why there is a need for classification systems. It further considers why we need to define an estuary and its constituent parts, including the fundamental difficulty and dilemma of trying to define parts of a continuum, as a means to both understanding and managing that estuary. The review considers where an estuary starts and ends and the relative merits of defining estuaries in terms of their biology, physics, chemistry, geographic nature and socio-economic units. It briefly discusses the need for legal and planning definitions and the linkages between science and management. Following this, we present a generic framework for the definition, classification, monitoring, assessment, reporting and management of estuaries. In particular, it is argued that scientists should engage in the debate on the definition of estuaries for legal and socio-economic purposes. It is concluded here that as existing definitions will never be suitable for all needs, a different approach is required. The proposed ' Expert Judgement Checklist Approach ' could provide guidance for those needing to define/delimit an estuary while still acknowledging the inherent variability of such systems. The proposed system mostly relates to the European, temperate estuary, but there are lessons here for estuaries worldwide.

  12. Comparison of Nutrient Drivers and Response Metrics in Oregon Estuaries

    EPA Science Inventory

    With the goal of assessing sensitivity to nutrient enrichment, we present a cross-estuary comparison of nutrient sources, levels, and biological responses (phytoplankton and macroalgae) for thirteen Oregon estuaries. Nitrogen levels in the upstream portions of the estuaries are ...

  13. MAPPING BATHYMETRY AND BOTTOM TYPE IN A SHALLOW ESTUARY

    EPA Science Inventory

    Bathymetry and bottom type are important in characterizing estuaries and their ecology but hard to map, especially in shallow estuaries. Acoustic backscattering was used to remotely sense these properties in the shallow Slocums River Estuary of Massachusetts. Acoustic pulses were...

  14. DENSITY-DEPENDENT IMPACTS OF BIOIRRIGATION BY THE BURROWING SHRIMP UPOGEBIA PUGETTENSIS ON BENTHIC FLUXES AND POREWATER SOLUTE DISTRIBUTIONS IN PACIFIC NORTHWEST ESTUARIES

    EPA Science Inventory

    Burrowing thalassinid shrimp are major ecosystem engineering species of Pacific estuaries and can structure the physical, chemical, and biotic properties of sediments. Feeding and burrow irrigation by benthic organisms can increase the remineralization rates of organic material (...

  15. 75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-21

    ... the Final Estuary Habitat Restoration Strategy (67 FR 71942). Section 106(f) of the Act authorizes the... National Oceanic and Atmospheric Administration RIN 0648-XX00 Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration Strategy; Request for Public Comment...

  16. Distribution of polycyclic aromatic hydrocarbons in sediments from Yellow River Estuary and Yangtze River Estuary, China.

    PubMed

    Hui, Yamei; Zheng, Minghui; Liu, Zhengtao; Gao, Lirong

    2009-01-01

    Surface sediment samples collected from twenty-one sites of Yellow River Estuary and Yangtze River Estuary were determined for sixteen priority polycyclic aromatic hydrocarbons (PAHs) by isotope dilution GC-MS method. The total PAH contents varied from 10.8 to 252 ng/g in Yellow River Estuary sediment, and from 84.6 to 620 ng/g in Yangtze River Estuary sediment. The mean total PAH content of Yangtze River Estuary was approximately twofold higher than that of Yellow River Estuary. The main reasons for the difference may be the rapid industrial development and high population along Yangtze River and high silt content of Yellow River Estuary. The evaluation of PAH sources suggested that PAHs in two estuaries sediments estuaries were derived primarily from combustion sources, but minor amounts of PAHs were derived from petroleum source in Yellow River Estuary. PAHs may be primary introduced to Yellow River Estuary via dry/wet deposition, wastewater effluents, and accidental oil spills, and Yangtze River Estuary is more prone to be affected by wastewater discharge. PMID:20131590

  17. Tidal wetland conservation and restoration for flood mitigation in estuaries and deltas: examples and global potential

    NASA Astrophysics Data System (ADS)

    Temmerman, Stijn; Smolders, Sven; Stark, Jeroen; meire, patrick

    2014-05-01

    Low-lying and densely populated deltas and estuaries are world widely exposed to flood risks caused by storm surges. On the one hand, global change is increasing these flood risks through accelerating sea level rise and increasing storm intensity, but on the other hand, local-scale human impacts on deltas and estuaries are in many cases even more increasing the vulnerability to floods. Here we address the degradation and reclamation of tidal wetlands (i.e. salt marshes in the temperate zone and mangroves in the tropical zone) as a major source for increasing vulnerability to flooding of estuaries and deltas. Firstly, we present examples of flood mitigation by tidal wetland conservation and restoration, and secondly we explore the potentials and limitations for global application of this approach of ecosystem-based flood defense (see Temmerman et al. 2013). First, we use the Scheldt estuary (SW Netherlands and Belgium) as an example where historic wetland reclamation has importantly contributed to increasing flood risks, and where tidal marsh restoration on the previously reclaimed land is nowadays brought into large-scale practice as an essential part of the flood defense system. Based on data and hydrodynamic modelling, we show that large-scale historic marsh reclamation has largely reduced the water storage capacity of the estuary and has reduced the friction to propagating flood waves, resulting in an important landward increase of tidal and storm surge levels. Hydrodynamic model scenarios demonstrate how tidal and storm surge propagation through the estuary are affected by tidal marsh properties, including the surface area, elevation, vegetation and position of marshes along the estuary. We show that nowadays tidal wetland creation on previously reclaimed land is applied as an essential part of the flood defense system along the Scheldt estuary. Secondly, a global analysis is presented of the potential application of tidal wetlands in flood mitigation in estuaries and deltas worldwide. We discuss the societal benefits and drawbacks of wetland creation for flood defense, and provide an estimation of where on Earth this approach could be feasible. This shows that many of the largest urban populations that are at risk from coastal flooding, are located in large deltas and estuaries, such as in Southeast Asia, North America and Europe. We argue that many of these vulnerable areas are potentially well suited to include wetland conservation and restoration as an essential part of adaptation and mitigation strategies against storm surge flood risks. References: Temmerman S., Meire P., Bouma T.J., Herman P.M.J., Ysebaert T., De Vriend H.J. (2013) Ecosystem-based coastal defense in the face of global change. Nature, 504, P. 79-83, doi:10.1038/nature12859.

  18. United States Air Force 611th Air Support Group/Civil Engineering Squadron Elmendorf AFB, Alaska. Remedial investigation and feasibility study. Bullen Point Radar Installation, Alaska. Final report

    SciTech Connect

    Karmi, S.

    1996-03-18

    The United States Air Force (Air Force) has prepared this Remedial investigation/Feasibility Study (RI/FS) report as part of the Installation Restoration Program (IRP) to present results of RI/FS activities at five sites at the Bullen Point radar installation. The IRP provides for investigating, quantifying, and remediating environmental contamination from past waste management activities at Air Force installations throughout the United States.

  19. Morphodynamic equilibrium of alluvial estuaries

    NASA Astrophysics Data System (ADS)

    Tambroni, Nicoletta; Bolla Pittaluga, Michele; Canestrelli, Alberto; Lanzoni, Stefano; Seminara, Giovanni

    2014-05-01

    The evolution of the longitudinal bed profile of an estuary, with given plan-form configuration, subject to given tidal forcing at the mouth and prescribed values of water and sediment supply from the river is investigated numerically. Our main goal is to ascertain whether, starting from some initial condition, the bed evolution tends to reach a unique equilibrium configuration asymptotically in time. Also, we investigate the morphological response of an alluvial estuary to changes in the tidal range and hydrologic forcing (flow and sediment supply). Finally, the solution helps characterizing the transition between the fluvially dominated region and the tidally dominated region of the estuary. All these issues play an important role also in interpreting how the facies changes along the estuary, thus helping to make correct paleo-environmental and sequence-stratigraphic interpretations of sedimentary successions (Dalrymple and Choi, 2007). Results show that the model is able to describe a wide class of settings ranging from tidally dominated estuaries to fluvially dominated estuaries. In the latter case, the solution is found to compare satisfactory with the analytical asymptotic solution recently derived by Seminara et al. (2012), under the hypothesis of fairly 'small' tidal oscillations. Simulations indicate that the system always moves toward an equilibrium configuration in which the net sediment flux in a tidal cycle is constant throughout the estuary and equal to the constant sediment flux discharged from the river. For constant width, the bed equilibrium profile of the estuarine channel is characterized by two distinct regions: a steeper reach seaward, dominated by the tide, and a less steep upstream reach, dominated by the river and characterized by the undisturbed bed slope. Although the latter reach, at equilibrium, is not directly affected by the tidal wave, however starting from an initial uniform stream with the constant 'fluvial' slope, the final equilibrium state is reached through an erosional wave, which leads to bed degradation of the upstream 'fluvial reach'. For a given river discharge, the length of the tidal reach increases quite rapidly with tidal amplitude, up to some threshold value of the tidal amplitude above which the length of the estuary becomes comparable with the length of the tidal wave. When the channel plan-form is convergent, deposition of sediments of fluvial origin in the funnel-shaped region drastically changes the equilibrium configuration. The effect of an increasing channel convergence is thus to induce bed aggradation close to the inlet. Nevertheless, tidal forcing only slightly changes the non-tidal profile. The effect of increasing tidal oscillations again leads to an increase of the bed slope at the inlet and to a general bed degradation upstream. The effects of varying sediment supply, flow discharge and river width in the upstream reach have also been investigated and play an important role. Further geomorphological implications of these results will be discussed at the meeting. References Dalrymple, R. W., and K. Choi (2007), Morphologic and facies trends through the fluvialmarine transition in tide-dominated depositional systems: A schematic framework for environmental and sequence-stratigraphic interpretation, Earth-Science Reviews, 81(3-4), 135-174, doi:10.1016/j.earscirev.2006.10.002. Seminara, G., M. Bolla Pittaluga, and N. Tambroni (2012), Morphodynamic equilibrium of tidal channels, Environmental Fluid Mechanics: Memorial Volume in Honour of Prof. Gerhard H. Jirka, 153-174

  20. Assessing sediment contamination in estuaries.

    PubMed

    Chapman, P M; Wang, F

    2001-01-01

    Historic and ongoing sediment contamination adversely affects estuaries, among the most productive marine ecosystems in the world. However, all estuaries are not the same, and estuarine sediments cannot be treated as either fresh or marine sediments or properly assessed without understanding both seasonal and spatial estuarine variability and processes, which are reviewed. Estuaries are physicochemically unique, primarily because of their variable salinity but also because of their strong gradients in other parameters, such as temperature, pH, dissolved oxygen, redox potential, and amount and composition of particles. Salinity (overlying and interstitial) varies spatially (laterally, vertically) and temporally and is the controlling factor for partitioning of contaminants between sediments and overlying or interstitial water. Salinity also controls the distribution and types of estuarine biota. Benthic infauna are affected by interstitial salinities that can be very different than overlying salinities, resulting in large-scale seasonal species shifts in salt wedge estuaries. There are fewer estuarine species than fresh or marine species (the paradox of brackish water). Chemical, toxicological, and community-level assessment techniques for estuarine sediment are reviewed and assessed, including chemistry (grain size effects, background enrichment, bioavailability, sediment quality values, interstitial water chemistry), biological surveys, and whole sediment toxicity testing (single-species tests, potential confounding factors, community level tests, laboratory-to-field comparisons). Based on this review, there is a clear need to tailor such assessment techniques specifically for estuarine environments. For instance, bioavailability models including equilibrium partitioning may have little applicability to estuarine sediments, appropriate reference comparisons are difficult in biological surveys, and there are too few full-gradient estuarine sediment toxicity tests available. Specific recommendations are made to address these and other issues. PMID:11351413

  1. Protocols for Monitoring Habitat Restoration Projects in the Lower Columbia River and Estuary

    SciTech Connect

    Roegner, G. Curtis; Diefenderfer, Heida L.; Borde, Amy B.; Thom, Ronald M.; Dawley, Earl M.; Whiting, Allan H.; Zimmerman, Shon A.; Johnson, Gary E.

    2008-04-25

    Protocols for monitoring salmon habitat restoration projects are essential for the U.S. Army Corps of Engineers' environmental efforts in the Columbia River estuary. This manual provides state-of-the science data collection and analysis methods for landscape features, water quality, and fish species composition, among others.

  2. D-21B RBCC Modification Feasibility Study

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This report presents a feasibility study on the modifications required to re-engine the Lockheed D-21 Drone for use as a NASA RBCC engine. An introduction, background information, engine configuration and performance, propulsion system integration, loads/thermal analysis, avionics/systems, flight test results, costs and work schedule, and some conclusions are presented.

  3. Tidal Asymmetry in Amazon Estuary

    NASA Astrophysics Data System (ADS)

    Vinzon, S. B.; Gallo, M. N.; Fernandes, R. D.

    2007-05-01

    Estuaries and coastal areas are the last reservoir of fine sediments yield in the continental basins. One of the most interesting questions for each particular system is where the fine sediments are trapped in larger quantities. In the early 90's, a thorough measurement project was held over the Amazon Continental Shelf and coastal zone. One of the results of this project was the register of a huge amount of sediments in suspension over the Shelf, where the turbidity maximum would be located. In order to promote the formation of a turbidity maximum zone, conditions for trapping and deposition are necessary as well as a source of energy to keep sediments in suspension, in general in a feed back way. Several mechanisms can be pointed as responsible for trapping sediments in estuaries and coastal areas. Sediments are carried by currents and the question could be established as which are the main features in the hydrodynamics which contributes to the formation of the turbidity maximum? Flocculation induced by the changes in the flow structure, mainly the reduction in turbulence, can be regarded as one of the mechanisms which contribute to the formation of the turbidity maximum In fact, in-situ measurements showed floc sizes as big as 600m over the Amazon Shelf. Other feature which strongly affects hydrodynamics and hence trapping sediments is the creation of recirculation zones, related to the estuarine morphology, this aspect, especially important in open areas, is also important in the Amazon Shelf. The role of the shear stress asymmetry and the transport capacity asymmetry both related to the salt stratification structure are also shown as important mechanisms for sediment trapping in this environment. Focusing the understanding of the dynamics of fine sediments in Amazon estuary, the tide asymmetry in the Amazon estuary is analyzed. Changes in the vertical tide asymmetry are observed along the estuary. A positive vertical tide asymmetry is observed in the estuarine region with river influence, which is not indicative of positive velocity asymmetry, as is currently considered for tidal bays, without significant river discharge. Over the Shelf, where salinity intrusion and fluid mud bottom layers occur, negative tidal asymmetry is observed. Causes for the changes of the asymmetry and their consequences for the sediment transport are addressed in this work.

  4. United States Air Force 611th Air Support Group Civil Engineering Squadron, Elmendorf AFB, Alaska. Remedial investigation and feasibility study Point Lay Radar Installation, Alaska. Final report

    SciTech Connect

    Karmi, S.

    1996-03-04

    The United States Air Force (Air Force) has prepared this Remedial Investigation/Feasibility Study (RI/FS) report to present the results of RI/FS activities at four sites located at the Point Lay radar installation. The remedial investigation (RI) field activities were conducted at the Point Lay radar installation during the summer of 1993. The four sites at Point Lay were investigated because they were suspected of being contaminated with hazardous substances. RI activities were conducted using methods and procedures specified in the RI/FS Work Plan, Sampling and Analysis Plan (SAP), and Health and Safety Plan.

  5. Towards medium-term (order of months) morphodynamic modelling of the Teign estuary, UK

    NASA Astrophysics Data System (ADS)

    Bernardes, Marcos E. C.; Davidson, Mark A.; Dyer, Keith R.; George, Ken J.

    2006-07-01

    The main objective of this paper is to address the principal mechanisms involved in the medium-term (order of months to years) morphodynamic evolution of estuaries through the application of a process-based numerical modelling. The Teign estuary (Teignmouth, UK) is the selected site. The system is forced by the macrotidal semi-diurnal tide in the English Channel and is perturbed to a minor extent by high river discharge events (freshets). Although waves have a definite influence on the adjacent coastal area, Wells (Teignmouth Quay Development Environmental Statement: Changes to Physical Processes. Report R.984c:140. ABP Marine Environmental Research Ltd., Southampton, 2002b) suggested that swell waves do not enter the estuary. Hence, wave effects are neglected in this study, as only tides and the river discharge are taken into account. The sediment grain size is highly variable, but mainly sandy. Within the frame of the COAST3D project ( http://www.hrwallingford.co.uk/projects/COAST3D ), four bathymetric surveys of the adjacent coastal area were carried out at a nearly weekly intervals. The outer estuary and the adjacent coastal area were also surveyed every 6 months as part of the COASTVIEW project ( http://thecoastviewproject.org ). Based on these data and on continuously measured parameters, such as water level, waves, wind and river discharge, numerical modelling of the morphodynamic processes can be tested. To replicate the morphological changes in the medium-term within a feasible simulation time, forcing conditions are reduced through the use of an input reduction method (called ensemble technique). In this study, simulations are based on the coupling between Telemac-2D and its non-cohesive sediment transport module, Sisyphe (version 5.3 for both modules). Three different sediment transport formulae were tested: (1) Engelund and Hansen (A monograph on sediment transport in alluvial streams, 3rd edn. Technological University of Denmark, Copenhagen, 1967) including the modifications proposed by Chollet and Cunge (J Hydraul Eng 17(1):1-13, 1979); (2) Bijker (Mechanics of sediment transport by the combination of waves and current. In: Design and reliability of coastal structures. 23rd international conference on Coastal Engineering, pp 147-173, 1968) and (3) Soulsby (Dynamics of Marine Sands. A manual for practical applications. HR Wallingford, Wallingford, p 142, 1997) modified version of van Rijn [J Hydraul Eng 110(10):1431-1456, 1984a, J Hydraul Eng 110(11):1613-1641, 1984b] formulation. Both a qualitative (i.e. visual comparison) and a quantitative tool [Brier Skill Score (BSS); described in Sutherland et al. in Coast Eng 51:917-939, 2004b] are applied to assess the similarity of simulations when compared to model predictions and observations. Tests confirmed the reliability and time efficiency of the ensemble technique, since it reproduced very well the results of a reference run, a computation based on the observed boundary conditions. For the spring-neap cycle modelled, the BSS was of 0.91 (a perfect modelling would have a BSS of 1), with a reduction in the simulation time on the order of 80%. For the 6-month-period simulation, results were also excellent: BSS=0.92 and a computer time reduction of 85%. In principle, this method has the advantage of being applied to any process-based numerical model.

  6. Country-wide assessment of estuary health: An approach for integrating pressures and ecosystem response in a data limited environment

    NASA Astrophysics Data System (ADS)

    Van Niekerk, L.; Adams, J. B.; Bate, G. C.; Forbes, A. T.; Forbes, N. T.; Huizinga, P.; Lamberth, S. J.; MacKay, C. F.; Petersen, C.; Taljaard, S.; Weerts, S. P.; Whitfield, A. K.; Wooldridge, T. H.

    2013-09-01

    Population and development pressures increase the need for proactive strategic management on a regional or country-wide scale - reactively protecting ecosystems on an estuary-by-estuary basis against multiple pressures is 'resource hungry' and not feasible. Proactive management requires a strategic assessment of health so that the most suitable return on investment can be made. A country-wide assessment of the nearly 300 functional South African estuaries examined both key pressures (freshwater inflow modification, water quality, artificial breaching of temporarily open/closed systems, habitat modification and exploitation of living resources) and health state. The method used to assess the type and level of the different pressures, as well as the ecological health status of a large number of estuaries in a data limited environment is described in this paper. Key pressures and the ecological condition of estuaries on a national scale are summarised. The template may also be used to provide guidance to coastal researchers attempting to inform management in other developing countries. The assessment was primarily aimed at decision makers both inside and outside the biodiversity sector. A key starting point was to delineate spatially the estuary functional zone (area) for every system. In addition, available data on pressures impacting estuaries on a national scale were collated. A desktop national health assessment, based on an Estuarine Health Index developed for South African ecological water requirement studies, was then applied systematically. National experts, all familiar with the index evaluated the estuaries in their region. Individual estuarine health assessment scores were then translated into health categories that reflect the overall status of South Africa's estuaries. The results showed that estuaries in the warm-temperate biogeographical zone are healthier than those in the cool-temperate and subtropical zones, largely reflecting the country's demographics and developmental pressures. A major finding was that, while a large number of South Africa's estuaries are still in an excellent to good condition, they tend to represent very small systems (<150 ha in size) in rural areas with few pressures. Larger systems, which are more important as nursery grounds because of their size, and also of higher economic and ecological importance, are in a fair to poor condition. This was due to pressures within the catchments influencing these downstream systems, and degradation as a result of direct development within the estuary functional zone.

  7. AFS Estuaries Section - A Successful Partnership

    EPA Science Inventory

    The Estuaries Section of the American Fisheries Society offers travel awards to students in support of their attendance and presentations at the AFS meeting. Since 2007, the Southern Association of Marine Laboratories has partnered with the Estuaries Section to sponsor two stude...

  8. NEW HAMPSHIRE ESTUARIES PROJECT MANAGEMENT PLAN

    EPA Science Inventory

    This Comprehensive Conservation and Management Plan of the New Hampshire Estuaries Project presents a broad framework and specific list of actions to protect and enhance the environmental quality of the estuaries of the State of New Hampshire. It is intended to be a guide for all...

  9. Dissolved Oxygen Data for Coos Estuary (Oregon)

    EPA Science Inventory

    The purpose of this product is the transmittal of dissolved oxygen data collected in the Coos Estuary, Oregon to Ms. Molly O'Neill (University of Oregon), for use in her studies on the factors influencing spatial and temporal patterns in dissolved oxygen in this estuary. These d...

  10. NEW HAMPSHIRE ESTUARIES PROJECT MANAGEMENT PLAN, 2000

    EPA Science Inventory

    The Comprehensive Conservation and Management Plan of the New Hampshire Estuaries Project presents a broad framework and specific list of actions to protect and enhance the environmental quality of the estuaries of the State of New Hampshire. It is intended to be a guide for all ...

  11. NEW HAMPSHIRE'S ESTUARIES, THE STATE OF

    EPA Science Inventory

    The State of the New Hampshire Estuary Report describes the region's valuable natural resources, explains how natural resources are linked to the cultural and economic well being of New Hampshire, and identifies threats to these resources. This State of the Estuaries Report summa...

  12. A Climate Ready Estuaries Vulnerability Assessment

    EPA Science Inventory

    The purpose of the the Climate Ready Estuaries program is to build capacity in the National Estuary Programs (NEPs) for local leadership and expertise to adapt to the effects of climate change through a joint effort with the NEPs and EPA.

    Background
    The Climate Ready...

  13. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY10 Annual Report

    SciTech Connect

    Johnson, Gary E.

    2010-10-26

    The Estuary/Ocean Subgroup (EOS) is part of the research, monitoring, and evaluation (RME) effort that the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. The EOS is one of multiple work groups in the federal research, monitoring, and evaluation (RME) effort developed in response to responsibilities arising from the Endangered Species Act as a result of operation of the FCRPS. The EOS is tasked by NOAA Fisheries and the Action Agencies to design and coordinate implementation of the federal RME plan for the lower Columbia River and estuary, including the plume.

  14. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring, and Evaluation, FY07 Annual Report

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2007-10-10

    This annual report is a deliverable for fiscal year 2007 (FY07) for Project 2002-077-00, Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to responsibilities arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In FY07, EOS project accomplishments included 1) subgroup meetings; 2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; 3) project management via the project tracking system, PISCES; 4) quarterly project status reports; and 5) a major revision to the Estuary RME Plan (new version September 2007) based on comments by EOS members and invited reviewers.

  15. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring and Evaluation - FY07 Annual Report.

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2007-10-10

    This annual report is a deliverable for fiscal year 2007 (FY07) for Project 2002-077-00, Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort of the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to responsibilities arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In FY07, EOS project accomplishments included (1) subgroup meetings; (2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; (3) project management via the project tracking system, PISCES; (4) quarterly project status reports; and (5) a major revision to the Estuary RME Plan (new version September 2007) based on comments by EOS members and invited reviewers.

  16. Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection - May 16, 2011

    EPA Science Inventory

    We examined the role of the ocean –estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

  17. Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection - May 16, 2011

    EPA Science Inventory

    We examined the role of the ocean estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

  18. Sault Tribe Wind Energy Feasibility Study

    SciTech Connect

    Toni Osterhout; Global Energy Concepts

    2005-07-31

    The Sault Tribe conducted a feasibility study on tribal lands in the Upper Peninsula of Michigan to determine the technical and economic feasibility of both small and large-scale wind power development on tribal lands. The study included a wind resource assessment, transmission system analysis, engineering and regulatory analyzes and assessments.

  19. Water Column Methylation in Estuaries

    NASA Astrophysics Data System (ADS)

    Schartup, A. T.; Calder, R.; Soerensen, A. L.; Mason, R. P.; Balcom, P. H.; Sunderland, E. M.

    2014-12-01

    Methylmercury (MeHg) is a neurotoxin that bioaccumulates in aquatic food webs and affects humans and wildlife through fish consumption. Many studies have measured active methylation/demethylation in ocean margin sediments but few have reported similar rates for the marine water column. This presentation will review available evidence for water column methylation in estuaries, including new experimental measurements of methylation/demethylation rates from a deep subarctic fjord in Labrador Canada collected in Spring and Fall of 2012-2013. We used these and other data to construct a mass budget for MeHg in the estuary and show that water column methylation (with rates ranging from 1.5 to 2.8 % day-1), is the largest contributor, followed by inputs from rivers (4.9 mol year-1), to the in situ pool of MeHg available for uptake by biota. By contrast, the sediment in this system is a net sink for MeHg (-1.5 mol year-1). We discuss the relationship between observed MeHg and other ancillary environmental factors (organic carbon, sulfur and nutrients) as well as implications for the response time of fish to future changes in mercury inputs.

  20. Salinity of the Delaware Estuary

    USGS Publications Warehouse

    Cohen, Bernard; McCarthy, Leo T., Jr.

    1962-01-01

    The purpose of this investigation was to obtain data on and study the factors affecting the salinity of the Delaware River from Philadelphia, Pa., to the Appoquinimink River, Del. The general chemical quality of water in the estuary is described, including changes in salinity in the river cross section and profile, diurnal and seasonal changes, and the effects of rainfall, sea level, and winds on salinity. Relationships are established of the concentrations of chloride and dissolved solids to specific conductance. In addition to chloride profiles and isochlor plots, time series are plotted for salinity or some quantity representing salinity, fresh-water discharge, mean river level, and mean sea level. The two major variables which appear to have the greatest effect on the salinity of the estuary are the fresh-water flow of the river and sea level. The most favorable combination of these variables for salt-water encroachment occurs from August to early October and the least favorable combination occurs between December and May.

  1. Remedial investigation/feasibility study Work Plan and addenda for Operable Unit 4-12: Central Facilities Area Landfills II and III at the Idaho National Engineering Laboratory

    SciTech Connect

    Keck, K.N.; Stormberg, G.J.; Porro, I.; Sondrup, A.J.; McCormick, S.H.

    1993-07-01

    This document is divided into two main sections -- the Work Plan and the addenda. The Work Plan describes the regulatory history and physical setting of Operable Unit 4-12, previous sampling activities, and data. It also identifies a preliminary conceptual model, preliminary remedial action alternatives, and preliminary applicable or relevant and appropriate requirements. In addition, the Work Plan discusses data gaps and data quality objectives for proposed remedial investigation activities. Also included are tasks identified for the remedial investigation/feasibility study (RI/FS) and a schedule of RI/FS activities. The addenda include details of the proposed field activities (Field Sampling Plan), anticipated quality assurance activities (Quality Assurance Project Plan), policies and procedures to protect RI/FS workers and the environment during field investigations (Health and Safety Plan), and policies, procedures, and activities that the Department of Energy will use to involve the public in the decision-making process concerning CFA Landfills II and III RI/FS activities (Community Relations Plan).

  2. Major hydrogeochemical processes in an acid mine drainage affected estuary.

    PubMed

    Asta, Maria P; Calleja, Maria Ll; Pérez-López, Rafael; Auqué, Luis F

    2015-02-15

    This study provides geochemical data with the aim of identifying and quantifying the main processes occurring in an Acid Mine Drainage (AMD) affected estuary. With that purpose, water samples of the Huelva estuary were collected during a tidal half-cycle and ion-ion plots and geochemical modeling were performed to obtain a general conceptual model. Modeling results indicated that the main processes responsible for the hydrochemical evolution of the waters are: (i) the mixing of acid fluvial water with alkaline ocean water; (ii) precipitation of Fe oxyhydroxysulfates (schwertmannite) and hydroxides (ferrihydrite); (iii) precipitation of Al hydroxysulfates (jurbanite) and hydroxides (amorphous Al(OH)3); (iv) dissolution of calcite; and (v) dissolution of gypsum. All these processes, thermodynamically feasible in the light of their calculated saturation states, were quantified by mass-balance calculations and validated by reaction-path calculations. In addition, sorption processes were deduced by the non-conservative behavior of some elements (e.g., Cu and Zn). PMID:25530015

  3. ENGINEERING FEASIBILITY AND ECONOMICS OF CO2 SEQUESTRATION/USE ON AN EXISTING COAL-FIRED POWER PLANT: A LITERATURE REVIEW

    SciTech Connect

    Carl R. Bozzuto; Nsakala ya Nsakala

    2000-01-31

    The overall objective of this study is to evaluate the technical feasibility and the economics of alternate CO{sub 2} capture and sequestration/use technologies for retrofitting an existing pulverized coal-fired power plant. To accomplish this objective three alternative CO{sub 2} capture and sequestration systems will be evaluated to identify their impact on an existing boiler, associated boiler auxiliary components, overall plant operation and performance and power plant cost, including the cost of electricity. The three retrofit technologies that will be evaluated are as follows: (1) Coal combustion in air, followed by CO{sub 2} separation from flue gas with Kerr-McGee/ABB Lummus Global's commercial MEA-based absorption/stripping process. (2) Coal combustion in an O{sub 2}/CO{sub 2} environment with CO{sub 2} recycle. (3) Coal combustion in air with oxygen removal and CO{sub 2} captured by tertiary amines In support of this objective and execution of the evaluation of the three retrofit technologies a literature survey was conducted. It is presented in an ''annotated'' form, consistent with the following five sections: (1) Coal Combustion in O{sub 2}/CO{sub 2} Media; (2) Oxygen Separation Technologies; (3) Post Combustion CO{sub 2} Separation Technologies; (4) Potential Utilization of CO{sub 2}; and (5) CO{sub 2} Sequestration. The objective of the literature search was to determine if the three retrofit technologies proposed for this project continue to be sound choices. Additionally, a review of the literature would afford the opportunity to determine if other researchers have made significant progress in developing similar process technologies and, in that context, to revisit the current state-of-the-art. Results from this literature survey are summarized in the report.

  4. Alien reef-building polychaete drives long-term changes in invertebrate biomass and diversity in a small, urban estuary

    NASA Astrophysics Data System (ADS)

    McQuaid, K. A.; Griffiths, C. L.

    2014-02-01

    Two of the greatest threats to native biodiversity are the construction of artificial structures in natural environments and the introduction of invasive species. As the development and urbanisation of estuaries continues at an increasing rate worldwide, these environments are being simultaneously affected by these threats. This study quantifies the spread of an invasive reef-building polychaete, Ficopomatus enigmaticus, in a small, highly manipulated urban estuary in South Africa and investigates its role as an ecosystem engineer. Anthropogenic changes to the Zandvlei Estuary, including construction of a rubble weir and canalisation near the estuary mouth, construction of an extensive marina development and hardening of the banks with concrete, have facilitated the expansion of F. enigmaticus. The standing stock of F. enigmaticus increased from 13.69 t, as measured in 1986, to 50.03 t in 2012, due both to increase in the total area colonised and standing stock per m2. Since F. enigmaticus reefs support a greater biomass of infauna than adjacent sandy areas, total invertebrate biomass in the estuary is estimated to have increased from less than 0.30 t in 1942, to over 56.80 t in 2012, due mainly to hardening of banks in parts of the main estuary with concrete and construction of a marina system. A positive correlation between reef mass and infaunal biomass, density and diversity was also found.

  5. Assessing the susceptibility of two UK estuaries to nutrient enrichment

    NASA Astrophysics Data System (ADS)

    Kadiri, Margaret; Bockelmann-Evans, Bettina; Rauen, William B.

    2014-10-01

    The susceptibility of two UK estuaries, the Severn and Solva Estuaries to the risks and impacts of nutrient enrichment was investigated in this study by examining nutrients, dissolved oxygen (DO) and turbidity concentrations in the estuaries and applying a risk assessment model based on the UK's Comprehensive Studies Task Team (CSTT) modelling approach. Both estuaries were found to be nutrient enriched. However, there was no evidence of oxygen depletion in the Severn and algal blooms were not observed due to high turbidity, strong tidal currents and tidally induced vertical mixing conditions in the estuary. Although algal blooms were observed in the Solva Estuary, the estuary was well-oxygenated due to the relatively high water exchange rate and consistent rapid flushing in the estuary. The conditions in the Solva Estuary were predicted to be favourable for phytoplankton productivity and the wider potential implications for future water quality protection strategies in the Solva were discussed.

  6. Estimating bankfull discharge and depth in ungauged estuaries

    NASA Astrophysics Data System (ADS)

    Gisen, Jacqueline Isabella Anak; Savenije, Hubert H. G.

    2015-04-01

    It is difficult to measure river discharge accurately in an estuary, and particularly, in the region where the tidal flow dominates over the river discharge. River discharge is important for the morphology and hydrodynamics of estuaries as it influences the salt intrusion process, tidal dynamics, freshwater supply (water resources management), and the occurrence of floods. Here we try to derive river regime characteristics from the seaward end: the estuary. It is found that there are empirical relationships that link the geometry of an estuary to its river regime, which can be used to estimate river discharge characteristics with the least of data available. The aims of this study are: (1) to derive empirical relations between geometrical characteristics of estuaries and the bankfull discharge; (2) to explore a physical explanation for this relation; and (3) to estimate the bankfull discharge in estuaries. The physical connection between an estuary and its river regime is found by combining estuary shape analysis, tidal dynamic analysis, and Lacey's hydraulic geometry theory. The relationships found between the estuary depth, width, and bankfull river discharge have been tested in 23 estuaries around the world (including seven recently surveyed estuaries). From the analysis, it shows that the depth of an estuary is a function of the bankfull flood discharge to the power of 1/3, which is in agreement with Lacey's formula. This finding not only provides a method to estimate estuary depth, it also allows estimating flood discharge characteristics from readily available estuary shape indicators.

  7. EPA'S BENTHIC HABITAT DATA FOR YAQUINA ESTUARY

    EPA Science Inventory

    Scientists at EPA's National Health and Environmental Effects Research Laboratory, Western Ecology Division (WED) have been studying seafloor (benthic) habitats in Yaquina estuary for several years. Those studies were conducted as parts of several research projects, including: e...

  8. Microplastic in three urban estuaries, China.

    PubMed

    Zhao, Shiye; Zhu, Lixin; Li, Daoji

    2015-11-01

    Estuarine Microplastics (MPs) are limited to know globally. By filtering subsurface water through 330 μm nets, MPs in Jiaojiang, Oujiang Estuaries were quantified, as well as that in Minjiang Estuary responding to Typhoon Soulik. Polymer matrix was analyzed by Raman spectroscopy. MP (<5 mm) comprised more than 90% of total number plastics. The highest MPs density was found in Minjiang, following Jiaojiang and Oujiang. Fibers and granules were the primary shapes, with no pellets found. Colored MPs were the majority. The concentrations of suspended microplastics determine their bioavailability to low trophic organisms, and then possibly promoting the transfer of microplastic to higher trophic levels. Polypropylene and polyethylene were the prevalent types of MPs analyzed. Economic structures in urban estuaries influenced on MPs contamination levels. Typhoon didn't influence the suspended MP densities significantly. Our results provide basic information for better understanding suspended microplastics within urban estuaries and for managerial actions. PMID:26312741

  9. PECONIC ESTUARY PROGRAM TIDAL CREEK STUDY

    EPA Science Inventory

    EEA evaluated ten tidal creeks throughout the Peconic Estuary representing a wide range of watershed variables. Primary focus was directed towards the collection and analysis of the macrobenthic invertebrate communities of these ten tidal creeks. Analysis of the macrobenthic comm...

  10. ECOLOGICAL CONDITION OF SOUTH FLORIDA ESTUARIES

    EPA Science Inventory

    An assessment of the ecological condition of south Florida estuaries based on regional probabilistic monitoring was conducted during the summer of 1995. Samples and data were collected on water and sediment quality, benthos, and fish tissue contaminants. Elevated concentrations o...

  11. The Peel Inlet-Harvey Estuary Study.

    ERIC Educational Resources Information Center

    Walker, Warren; Black, Ronald

    1979-01-01

    Describes how the department of physics of the Western Australian Institute of Technology (WAIT) has been involved in the Peel Inlet-Harvey Estuary study. An appendix which presents the departmental approach to curriculum matters is also included. (HM)

  12. Water renewal timescales in the Scheldt Estuary

    NASA Astrophysics Data System (ADS)

    de Brye, Benjamin; de Brauwere, Anouk; Gourgue, Olivier; Delhez, Eric J. M.; Deleersnijder, Eric

    2012-06-01

    Using the concepts of the Constituent-oriented Age and Residence time Theory (CART), we compute timescales related to the water renewal in the Scheldt Estuary (The Netherlands/Belgium). Three different timescales are used to better understand and characterize the dynamics of the estuary: the age of the renewing water, the residence time and the exposure time. The residence time is the time taken by a water parcel to leave the estuary for the first time while the exposure time is the total time spent by a water parcel in the estuary including re-entries. The age of a renewing water parcel is defined as the time elapsed since it entered the estuary. The renewing water was split into three types: the water originating from the sea, the water originating from the upstream fresh tidal rivers and the water originating from the different canals and docks connected to the estuary. Every timescale is computed at any time and position by means of the finite-element, unstructured-mesh model SLIM. This results in movies of the timescale fields (shown as Supplementary material), allowing a detailed analysis of their spatial and temporal variabilities. The effect of the M2 tide and the discharge regime (winter, summer or average situation) on the timescales is also investigated. Tidally-averaged timescales vary little over the width of the estuary and hence exhibit a virtually one-dimensional behaviour. However, around these average values, the timescales can vary hugely over a tidal cycle, with amplitudes that significantly depend on the space coordinates. The reason thereof has yet to be elucidated. These results underscore the need for two- or three-dimensional models with high temporal resolution for investigating the dynamics of the Scheldt Estuary.

  13. Mixing in the Amazon estuary

    NASA Astrophysics Data System (ADS)

    Bezerra, M. O.

    2010-05-01

    The research area of this work is located at the estuary of the Amazon River (Brazil), near the river mouth. The results of air movement analysis on the surface atmospheric circulation over the Mouth of the Amazonas River, salinity and temperature measures as well as measurements of currents, carried out along a longitudinal section in the navigation canal region of the Northern Bar of the Amazon River (Barra Norte do Rio Amazonas) in June 2006, during the river flood season in the quadrature tide. The dynamics effects affect hydrodynamic,meteorological and hydrographical parameters at the river mouth. The conclusion drawn include that: a) the saline wedge-type stratification can be detected approximately 100km away from the mouth of the Amazon River during the end of the rainy season in the quadrature tide; b) probably, at the Amazon estuary the quadrature entrainment processes are dominant and they are the ones responsible for increased salinity detected in the surface layer, whereas turbulence scattering mixing is not so important. c) The large flow of fresh water from the Amazon River at the end of the rainy season implies the displacement of the saline front position over the internal Amazon continental platform, and d) The tidal wave shows a positive asymmetry in the canal, with floods lasting less than in the ebb tide. This asymmetry decreases towards the ocean, eventually becoming reversed in the presence of a saline wedge. The speeds, however, have a negative asymmetry, with more intense ebb tides, due to the river flow and is more evident by the existence of quadrature tides.

  14. Estuaries.

    ERIC Educational Resources Information Center

    Awkerman, Gary L.

    This publication is designed for use in standard science curricula to develop oceanologic manifestations of certain science topics. Included are teacher guides, student activities, and demonstrations designed to impart ocean understanding to high school students. When the student has completed this unit, he should be able to: (1) define an…

  15. Sonar Investigation of Sediment Deposition Patterns in the Delaware River Estuary

    NASA Astrophysics Data System (ADS)

    Walsh, D. R.; Sommerfield, C. K.

    2002-12-01

    Sedimentation in the Delaware River Estuary is influenced by natural hydrographic properties and engineering practices such as channel dredging and shoreline bulkheading, which influence sediment transport among its subenvironments. To better understand the regional sediment dynamics of this estuary, bottom sediments and morphologies were mapped using 390 miles of dual-frequency side-scan and Chirp sonar data between Trenton, NJ and New Castle, DE, a highly urbanized region. Sediment grabs (188) and cores (48) were collected to groundtruth the sonar data. Sonar imagery and grain size analysis reveal a sediment textural pattern that, in general, parallels the longitudinal salinity gradient of the estuary. In the northern extent of the study area (0-1 PSU), fluvial sands grade down estuary to muddy sands of possible marine origin in the southern extent (1-5 PSU). At the head of the salinity intrusion, three distinct locations of low acoustic backscatter are present within a larger area of higher backscatter. The low backscatter bottom corresponds to seasonally active mud deposits, whereas the high backscatter characterizes a dense mud bottom, mantled by a mobile veneer of sand and gravel. The zones of active deposition compose merely 8% of the total area of study, yet they contain a significant fraction of the suspended sediment inventory. The depositional zones are interpreted to reflect localized suspended sediment trapping, likely due to flocculation, as well as other processes that maintain the estuary turbidity maximum. The new sonar imagery has provided important insight into sediment budgetary and contaminant transport issues in the Delaware River Estuary; timeseries measurements of sediment transport are needed to elucidate the physical processes responsible for sediment trapping and deposition in the turbidity maximum region.

  16. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2005

    SciTech Connect

    Diefenderfer, Heida L.; Thom, Ronald M.; Borde, Amy B.; Roegner, G. C.; Whiting, Allan H.; Johnson, Gary E.; Dawley, Earl; Skalski, John R.; Vavrinec, John; Ebberts, Blaine D.

    2006-12-20

    This report is the second annual report of a six-year project to evaluate the cumulative effects of habitat restoration projects in the Columbia River Estuary, conducted by Pacific Northwest National Laboratory's Marine Sciences Laboratory, NOAA's National Marine Fisheries Service Pt. Adams Biological Field Station, and the Columbia River Estuary Study Taskforce for the US Army Corps of Engineers. In 2005, baseline data were collected on two restoration sites and two associated reference sites in the Columbia River estuary. The sites represent two habitat types of the estuary--brackish marsh and freshwater swamp--that have sustained substantial losses in area and that may play important roles for salmonids. Baseline data collected included vegetation and elevation surveys, above and below-ground biomass, water depth and temperature, nutrient flux, fish species composition, and channel geometry. Following baseline data collection, three kinds of restoration actions for hydrological reconnection were implemented in several locations on the sites: tidegate replacements (2) at Vera Slough, near the city of Astoria in Oregon State, and culvert replacements (2) and dike breaches (3) at Kandoll Farm in the Grays River watershed in Washington State. Limited post-restoration data were collected: photo points, nutrient flux, water depth and temperature, and channel cross-sections. In subsequent work, this and additional post-restoration data will be used in conjunction with data from other sites to estimate net effects of hydrological reconnection restoration projects throughout the estuary. This project is establishing methods for evaluating the effectiveness of individual projects and a framework for assessing estuary-wide cumulative effects including a protocol manual for monitoring restoration and reference sites.

  17. Simulating Suspended Silt Concentrations in the Ems Estuary, The Netherlands

    NASA Astrophysics Data System (ADS)

    Grasmeijer, B. T.

    2009-04-01

    1 Introduction The Ems Estuary is situated in the North-east Netherlands on the border with Germany. Its area, including the tidal river and excluding the outer delta, is 500 km2. The area of the outer delta is 100 km2. The length of the estuary from the inlet to the town of Leer in Germany is approximately 75 km. The mean tidal range varies over years (de Jonge, 1992), but is approximately 2.3 m near the island of Borkum (tidal inlet) and approximately 3.2 m near the town of Emden in Germany. The estuary receives water from the rain-fed River Ems (approximately 115 m3/s on average). A second much smaller freshwater input emanates from the small canalized river Westerwoldsche Aa (12.5 m3/s on average). These discharges vary strongly within and between years. The result of the interaction between freshwater discharge and seawater brought in by the tide is a salinity gradient, the length and position of which is strongly dependent on the water discharge by the rivers. The present morphology of the estuary is the result of natural processes such as tidal currents, wind and wave driven currents and river discharge, resulting in sediment trans-port and sedimentation and erosion patterns. These natural processes are affected by human interferences like maintenance dredging of the navigation channels, land reclamation, building of dikes, etc. The greatest changes in the last 50 years in the physical functioning of the Ems estuary have been the increased sea level and tidal range, the increased amplitude and frequency of storm surge, and greatly increased turbidity and sediment concentrations (particularly near the estuarine turbidity maximum). Much of the changes can be traced directly or indirectly to anthropogenic influence. 2 Aim and approach We studied the hydrodynamics and morphodynamics of the Ems estuary. One of the aims was to gain more insight in the behaviour of the suspended silt concentrations in the estuary and the anthropogenic influence thereon. We applied a beta release of the state-of-the-art Delft3D numerical model for this purpose. The model includes a new sediment transport module published by Van Rijn (2007, 2007a). The vertical distribution of the suspended sediment concentration in the transport module depends on the effective settling velocity of the sediment, the bed shear velocity and the turbulence. The silt transport is simulated every time step together with the flow (online), which means that the impact of the calculated concentration is accounted for in the hydrodynamics. Major challenge was to accurately simulate the relatively high suspended silt concentrations observed near the estuarine turbidity maximum. 3 Results The paper will compare observed and predicted water levels, salinity distributions and suspended silt concentrations. Figure 1 shows an example of predicted depth-averaged suspended silt concentrations during spring high tide without waves. Under these conditions the depth-averaged concentrations decrease from about 2 kg/m3 in the Unterems (upstream of Emden) to almost zero seaward of Borkum. PIC Figure 1: Figure 2 Observed and predicted salinities in the upper part of the water column along the estuary The presence of waves will increase the concentrations on the shoals but have a limited effect on the concentrations in the channels. Figure 2 presents observed and predicted salinities along the estuary. The model results encouragingly agree with the observations. PIC 4 References De Jonge, V.N., 1992. Tidal flow and residual flow in the Ems estuary. Estuarine, Coastal and Shelf Science, 34: 1-22. Van Rijn, L.C., 2007. Unified View of Sediment Transport by Currents and Waves. I: Initiation of Motion, Bed Roughness, and Bed-Load Transport. Journal of Hydraulic Engineering, 133(6): 649-667. Van Rijn, L.C., 2007a. Unified View of Sediment Transport by Currents and Waves. II: Suspended Transport. Journal of Hydraulic Engineering, 133(6): 668-689.

  18. The Estuary Book: A Guide to Promoting Understanding and Regional Management of Maine's Estuaries and Embayments.

    ERIC Educational Resources Information Center

    Ruffing, Jenny

    The objective of this document is to provide information about estuaries, the impact of uses on the environmental health of an estuary, and what communities and concerned individuals can do to manage and protect their local estuarine resources successfully. Much of the information presented here pertains to other embayments along the Maine coast…

  19. Fish track wastewater pollution to estuaries.

    PubMed

    Schlacher, Thomas A; Liddell, Ben; Gaston, Troy F; Schlacher-Hoenlinger, Monika

    2005-08-01

    Excess nitrogen is a forceful agent of ecological change in coastal waters, and wastewater is a prominent source of nitrogen. In catchments where multiple sources of nitrogen pollution co-exist, biological indicators are needed to gauge the degree to which wastewater-N can propagate through the receiving food webs. The purpose of this study was to test whether estuarine fish are suitable as indicators of sewage-N pollution. Fish were analysed from three estuaries within a 100-km strip on the Australian East Coast. The estuaries differ substantially in wastewater loading: (1) the Maroochy Estuary receives a large fraction of the local shire's treated sewage, (2) the Mooloolah Estuary has no licensed treated wastewater outfalls but marinas/harbours and storm-water may contribute nitrogen, and (3) the Noosa Estuary which neither receives licensed discharges nor has suspected wastewater loads. Sampling for fish included both high rainfall ('wet' season) and low rainfall ('dry' season) periods. Muscle-delta15N was the variable predicted to respond to treated wastewater loading, reflecting the relative enrichment in 15N resulting from the treatment process and distinguishing it from alternative N sources such as fertiliser and natural nitrogen inputs (both 15N-depleted). Of the 19 fish species occurring in all three estuaries, those from the Maroochy Estuary had significantly elevated delta15N values (up to 9.9 per thousand), and inter-estuarine differences in fish-delta15N were consistent across seasons. Furthermore, not only did all fish from the estuary receiving treated wastewater carry a very distinctive sewage-N tissue signal, but enriched muscle-delta15N was also evident in all species sampled from the one estuary in which sewage contamination was previously only suspected (i.e. the Mooloolah Estuary: 0.2-4.8 per thousand enrichment over fish from reference system). Thus, fish-delta15N is a suitable indicator of wastewater-N not only in systems that receive large loads, but also for the detection of more subtle nitrogen inputs. Arguably, fish may be preferred indicators of sewage-N contamination because they: (1) integrate nitrogen inputs over long time periods, (2) have an element of 'ecological relevance' because fish muscle-delta15N reflect movement of sewage-N through the food chain, and (3) pollution assessments can usually be based on evidence from multiple species. PMID:15891851

  20. MOBILE BAY NATIONAL ESTUARY PROGRAM COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN

    EPA Science Inventory

    In simplest terms, an estuary is defined as an area where rivers meet the sea. They are transitional zones where freshwater rivers meet tidally influenced marine waters. Estuaries are considered environmentally and economically important because of their exceptional biological di...

  1. Origin and composition of particulate organic matter in a macrotidal turbid estuary: The Gironde Estuary, France

    NASA Astrophysics Data System (ADS)

    Savoye, Nicolas; David, Valrie; Morisseau, Franois; Etcheber, Henri; Abril, Gwenal; Billy, Isabelle; Charlier, Karine; Oggian, Georges; Derriennic, Herv; Sautour, Benot

    2012-08-01

    At the interface between continent and ocean, estuaries receive particles, and especially particulate organic matter (POM) originating from these two reservoirs, but also produce POM, through autochthonous primary production. The origin and composition of surface POM in the Gironde Estuary (SW France) and the environmental forcing of its variability was investigated using the data set produced by the French Coastal Monitoring Network SOMLIT (Service d'Observation en Milieu LITtoral; monthly like sampling during years 2007-2009). This estuary is considered as a model of macrotidal turbid estuaries. Using elemental and isotopic composition of the POM, we estimated that, at the inner estuary space scale and inter-annual time scale, surface particulate organic carbon (POC) was composed of terrestrial POM originated from the turbidity maximum (96.4%; refractory POC) and flood events (1.6%; labile and refractory POC), and of riverine (0.1%), estuarine (0.8%) and marine (1.1%) phytoplankton, i.e. that POC was 98% and 2% of terrestrial and phytoplankton origin, respectively. However, there was a clear spatial gradient: the phytoplankton contribution increases from ca. 1% in the upper and middle estuary to 8.5% in the lower estuary, where light condition is more favourable to plankton growth. The low contribution of phytoplankton to the POC is a characteristic of the Gironde estuary and contrast with other large temperate estuaries. Statistical analysis indicates that salinity, river flow and SPM concentration, and thus associated hydro-dynamic and sedimentary processes, were the only environmental forcings to the composition of surface POC in this system, at intra- and inter-annual time scale. In contrast, temperature and nutrient concentrations, and thus associated processes, do not force this composition of POC. By combining POC fluxes entering the inner estuary (literature data), POC loss as dissolved organic carbon and CO2 and as sediment trapping within the inner estuary (literature data), and our estimate of the composition of POC flux at the mouth of the estuary (96% and 4% of terrestrial and phytoplankton origin), a first-order net export of POC originating from the Gironde to the continental shelf was estimated: it amounts 48,150 tC yr-1, and is composed of 46,200 tC yr-1 of terrestrial material and of 1950 tC yr-1 of estuarine phytoplankton. POC exported by the Gironde Estuary is thus poorly bioavailable for shelf pelagic and benthic food webs.

  2. Multi-Scale Action Effectiveness Research in the Lower Columbia River and Estuary, 2012

    SciTech Connect

    Johnson, Gary E.; Sather, Nichole K.; Storch, Adam; Johnson, Jeff; Skalski, J. R.; Teel, D. J.; Brewer, Taylor; Bryson, Amanda J.; Dawley, Earl M.; Kuligowski, D. R.; Whitesel, T.; Mallette, Christine

    2013-11-30

    The study reported herein was conducted for the U.S. Army Corps of Engineers, Portland District (USACE) by researchers at the Pacific Northwest National Laboratory (PNNL), Oregon Department of Fish and Wildlife (ODFW), National Marine Fisheries Service (NMFS), University of Washington (UW), and U.S. Fish and Wildlife Service (USFWS). The goal of the study was to evaluate the ecological benefits of restoration actions for juvenile salmon in the lower Columbia River and estuary (LCRE; rkm 0–234).

  3. Evaluation of Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2010

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Thom, Ronald M.; Roegner, G. Curtis; Ebberts, Blaine D.; Skalski, John R.; Borde, Amy B.; Dawley, Earl; Coleman, Andre M.; Woodruff, Dana L.; Breithaupt, Stephen A.; Cameron, April; Corbett, C.; Donley, Erin E.; Jay, D. A.; Ke, Yinghai; Leffler, K.; McNeil, C.; Studebaker, Cindy; Tagestad, Jerry D.

    2012-05-01

    This is the seventh and final annual report of a project (2004–2010) addressing evaluation of the cumulative effects of habitat restoration actions in the 235-km-long lower Columbia River and estuary. The project, called the Cumulative Effects (CE) study, was conducted for the U.S. Army Corps of Engineers Portland District by a collaboration of research agencies led by the Pacific Northwest National Laboratory. We achieved the primary goal of the CE study to develop a methodology to evaluate the cumulative effects of habitat actions in the Columbia Estuary Ecosystem Restoration Program. We delivered 1) standard monitoring protocols and methods to prioritize monitoring activities; 2) the theoretical and empirical basis for a CE methodology using levels-of-evidence; 3) evaluations of cumulative effects using ecological relationships, geo-referenced data, hydrodynamic modeling, and meta-analyses; and 4) an adaptive management process to coordinate and coalesce restoration efforts in the LCRE. A solid foundation has been laid for future comprehensive evaluations of progress made by the Columbia Estuary Ecosystem Restoration Program to understand, conserve, and restore ecosystems in the lower Columbia River and estuary.

  4. The ecological condition of Veracruz, Mexico estuaries.

    PubMed

    Macauley, J M; Harwell, L C; Alafita, H V

    2007-10-01

    During June and July, 2002, forty-seven stations were sampled within estuaries along the gulf coast of the state of Veracruz, MX, using a probabilistic survey design and a common set of response indicators. The objective of the study was to collect information to assess the condition of estuarine waters within the state of Veracruz, and to provide data that would strengthen future assessments of Gulf of Mexico estuaries. Samples for water quality, sediment contaminants, sediment toxicity, and benthic populations were collected in a manner consistent with EPA's National Coastal Assessment (NCA). Data were evaluated by comparing indicator measurements to tropical waters threshold values cited in US EPA's National Coastal Condition Report II, 2004, for tropical waters. In Veracruz, 75% of the area sampled rated poor for water quality, attributed primarily to high concentrations reported for chlorophyll a, and dissolved nutrients. One percent of the area exhibited poor sediment quality, based on PAH and metals concentrations. Compared to US estuaries of the Gulf of Mexico, water quality observed in Veracruz estuaries was more affected by nutrient over-enrichment. The probabilitistic nature of the survey design allowed for the comparison of the condition of Veracruz and the US GOM estuaries. PMID:17295108

  5. Estuaries and coastal waters need help

    SciTech Connect

    Levenson, H.

    1987-11-01

    For years, our marine environments-estuaries, coastal waters, and the open ocean-have been used extensively by coastal communities and industries for the disposal of various wastes. Historically, marine waste disposal has been relatively cheap and has solved some short-term waste-management problems; however, its consequences include a general trend toward environmental degradation, particularly in estuaries and coastal waters. Thus, without protective measures, the next few decades will witness degradation in many estuaries and some coastal waters around the country. The extent of current degradation varies greatly around the country. Although it is difficult to ascertain cause and effect relationships, enough evidence exists to conclude that the pollutants in question include disease-causing microorganisms, oxygen-demanding substances, particulate material, metals, and organic chemicals. Two statutes form the basis of most federal regulatory efforts to combat marine pollution: the Marine Protection, Research, and Sanctuaries Act (MPRSA) and the Clean Water Act (CWA). The MPRSA regulates the dumping of wastes in coastal and open-ocean waters, whereas the CWA has jurisdiction over pipeline discharges in all marine waters, wastes dumped in estuaries, and runoff. Many people consider that the passage and implementation of these two acts and their ensuing amendments established a statutory structure sufficient to protect the nation's waters from pollution. However, these provisions have not protected some estuaries and coastal waters from degradation.

  6. Rapid barium removal in the Delaware estuary

    SciTech Connect

    Stecher, H.A. III; Kogut, M.B.

    1999-04-01

    Six profiles of dissolved barium covering the entire salinity range of the Delaware River and Bay estuary from March through September 1996 were collected and analyzed. The profiles are similar to one another in both shape and magnitude except for one attribute. A sudden ({le} 24 days), nearly complete (>90%) removal of dissolved Ba in midestuary occurs in mid-May followed by an 80% recovery in early June. This removal appears to be temporally and spatially coupled to the end of the spring bloom. Based on such episodic behavior, and on recent work with flocculation of diatom exudates, the authors conclude that the Ba depletion is caused by barite precipitation in the estuary during the late stages of the bloom. This would imply that lower estuary and inner coastal margin sediments associated with eutrophic estuaries receive a seasonal pulse of barite. The suddenness of this event also implies that sedimentary barite is strongly influenced by high productivity events. Comparison of the riverine Ba concentration with the effective riverine end member after desorptive barium release yields an estimated 30--40 nM Ba available from the suspended sediments as they enter the estuary. This estimate is supported by excess barium in unfiltered samples over filtered samples taken from the river and also by calculations done elsewhere.

  7. Environmental flow assessments for transformed estuaries

    NASA Astrophysics Data System (ADS)

    Sun, Tao; Zhang, Heyue; Yang, Zhifeng; Yang, Wei

    2015-01-01

    Here, we propose an approach to environmental flow assessment that considers spatial pattern variations in potential habitats affected by river discharges and tidal currents in estuaries. The approach comprises four steps: identifying and simulating the distributions of critical environmental factors for habitats of typical species in an estuary; mapping of suitable habitats based on spatial distributions of the Habitat Suitability Index (HSI) and adopting the habitat aggregation index to understand fragmentation of potential suitable habitats; defining variations in water requirements for a certain species using trade-off analysis for different protection objectives; and recommending environmental flows in the estuary considering the compatibility and conflict of freshwater requirements for different species. This approach was tested using a case study in the Yellow River Estuary. Recommended environmental flows were determined by incorporating the requirements of four types of species into the assessments. Greater variability in freshwater inflows could be incorporated into the recommended environmental flows considering the adaptation of potential suitable habitats with variations in the flow regime. Environmental flow allocations should be conducted in conjunction with land use conflict management in estuaries. Based on the results presented here, the proposed approach offers flexible assessment of environmental flow for aquatic ecosystems that may be subject to future change.

  8. SAN FRANCISCO ESTUARY PROJECT COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN

    EPA Science Inventory

    The Estuary, a significant natural resource, San Francisco Bay and the Delta combine to form the West Coast's largest estuary. The Estuary conveys the waters of the Sacramento and San Joaquin Rivers to the Pacific Ocean. It encompasses roughly 1,600 square miles, drains over 40 p...

  9. The Estuary Guide. Level 3: High School. Draft.

    ERIC Educational Resources Information Center

    Alexander, Glen; And Others

    Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the high school level seeks to teach what estuaries are; provide opportunities to practice decision-making that affects estuaries; and encourage students to…

  10. Facilitation of the Estuary/Ocean Subgroup and the Expert Regional Technical Group, Fiscal Year 2014 Annual Report

    SciTech Connect

    Johnson, Gary E.

    2014-09-01

    This document is the annual report for fiscal year 2014 for the project called Facilitation of the Estuary/Ocean Subgroup (EOS) and the Expert Regional Technical Group (ERTG). Pacific Northwest National Laboratory (PNNL) conducted the project for the Bonneville Power Administration. The EOS and ERTG are part of the research, monitoring, and evaluation and habitat restoration efforts, respectively, developed by the Action Agencies (BPA, U.S. Army Corps of Engineers) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System and implemented under the Columbia Estuary Ecosystem Restoration Program.

  11. Retention of riverine iron in estuaries

    NASA Astrophysics Data System (ADS)

    Mayer, Lawrence M.

    1982-06-01

    Retention of Fe flocs, resulting from the mixing of river water and seawater, was examined in three Maine estuaries. Riverine Fe was found to remain fairly conservative with salinity, implying that the process of floccufation does not necessarily remove Fe from water parcels. Laboratory experiments corroborated the field data by demonstrating that neither gravity nor suspended sediment were very effective in removing flocculated Fe from suspension. However, input of a tannery effluent did appear to result in scavenging of Fe from estuarine waters. Flocculated riverine Fe was found to increase considerably the Fe concentrations of estuarine bottom sediments, with the amount of iron per sediment specific surface area dependent on mean river flow entering an estuary. While no long term retention efficiencies could be calculated for these estuaries, it seems likely that a significant portion of flocculated riverine Fe escapes to shelf waters.

  12. Modeling tidal distortion in the Ogeechee Estuary

    NASA Astrophysics Data System (ADS)

    Bruder, Brittany; Bomminayuni, Sandeep; Haas, Kevin; Stoesser, Thorsten

    2014-10-01

    A 3D numerical model is used to simulate the distortion of tidal hydrodynamics in the Ogeechee Estuary, GA. The Ogeechee, like many estuaries found in the Southeastern US, consists of shallow channel networks and extensive intertidal storage in the form of wetlands. Such features are known to induce non-linear overtide generation and significant tidal distortion, otherwise known as tidal stage asymmetry. Simulations are run with varying parameters to assess their effects on modeling tidal distortion for the Ogeechee Estuary: bottom friction coefficients, enhanced wetland friction coefficients, and tidal flat elevations. To succinctly quantify the degree of distortion across the domain, the statistical parameters of skewness and asymmetry are calculated for time series of water surface heights and channel volume fluxes. The intertidal storage causes the peak flood flux to occur later and the peak ebb flux to occur earlier, thereby resulting in positive asymmetry for the volume flux for the full estuary. However, ebb dominance is a localized feature and varies throughout the estuary. Increasing the intertidal storage by lowering wetland elevation enhances the effects on high tide and volume flux magnitudes, decreasing the ebb-dominance and volume flux asymmetry typically associated with intertidal storage thereby indicating the importance of the wetland elevation over the total storage volume. Increased channel bottom friction reduces ebb-dominance by extending the duration of the falling tide. More interestingly, increased wetland friction reduces the influence of wetland intertidal storage on tidal distortion. The model suggests an increase in wetland friction does little to dampen wave propagation at high tide but rather impedes the lateral flooding of wetlands, reducing ebb dominance. Tidal flat elevation has the largest impact on distortion for the Ogeechee Estuary whereas enhanced wetland and bottom frictional influences on distortion are small, albeit not insignificant.

  13. Facilitation of the Estuary/Ocean Subgroup and the Expert Regional Technical Group, Fiscal Year 2013 Annual Report

    SciTech Connect

    Johnson, Gary E.; Sather, Nichole K.

    2013-10-30

    This project covers facilitation of the Estuary/Ocean Subgroup (EOS) for federal research, monitoring, and evaluation (RME) and the Expert Regional Technical Group (ERTG) for estuary habitat restoration. The EOS is part of the research, monitoring, and evaluation effort that the Action Agencies (Bonneville Power Administration [BPA], U.S. Army Corps of Engineers [Corps], U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to operation of the Federal Columbia River Power System (FCRPS). The EOS is tasked by National Marine Fisheries Service (NMFS) and the Action Agencies (AAs) to design and coordinate implementation of the federal RME plan for the lower Columbia River and estuary, including the river’s plume in the ocean. Initiated in 2002, the EOS is composed of members from BPA, the Corps, NMFS, and Pacific Northwest National Laboratory’s (PNNL’s) Marine Sciences Laboratory, and other agencies as necessary.

  14. National Estuary Program after four years: A report to congress

    SciTech Connect

    Not Available

    1992-04-01

    The National Estuary Program After Four Years: A Report to Congress is a status report on the National Estuary Program (NEP) and the seventeen Management Conferences that are part of the NEP. The Report is divided into: Part I Meeting a Need: The National Estuary Program; Part II Understanding Estuaries: The Key to Better Management; Part III Managing Estuaries: The Best Methods; Part IV Assessing the NEP: What Has Been Learned; Part V Looking to the Future: Trends and Needs; and Part VI Moving Ahead: The NEP Projects.

  15. Ecological Feasibility Studies in Restoration Decision Making

    NASA Astrophysics Data System (ADS)

    Hopfensperger, Kristine N.; Engelhardt, Katharina A. M.; Seagle, Steven W.

    2007-06-01

    The restoration of degraded systems is essential for maintaining the provision of valuable ecosystem services, including the maintenance of aesthetic values. However, restoration projects often fail to reach desired goals for a variety of ecologic, financial, and social reasons. Feasibility studies that evaluate whether a restoration effort should even be attempted can enhance restoration success by highlighting potential pitfalls and gaps in knowledge before the design phase of a restoration. Feasibility studies also can bring stakeholders together before a restoration project is designed to discuss potential disagreements. For these reasons, a feasibility study was conducted to evaluate the efficacy of restoring a tidal freshwater marsh in the Potomac River near Alexandria, Virginia. The study focused on science rather than engineering questions, and thus differed in approach from other feasibility studies that are mostly engineering driven. The authors report the framework they used to conduct a feasibility study to inform other potential restoration projects with similar goals. The seven steps of the framework encompass (1) initiation of a feasibility study, (2) compilation of existing data, (3) collection of current site information, (4) examination of case studies, (5) synthesis of information in a handbook, (6) meeting with selected stakeholders, and (7) evaluation of meeting outcomes. By conducting a feasibility study using the seven-step framework, the authors set the stage for conducting future compliance studies and enhancing the chance of a successful restoration.

  16. Ecological feasibility studies in restoration decision making.

    PubMed

    Hopfensperger, Kristine N; Engelhardt, Katharina A M; Seagle, Steven W

    2007-06-01

    The restoration of degraded systems is essential for maintaining the provision of valuable ecosystem services, including the maintenance of aesthetic values. However, restoration projects often fail to reach desired goals for a variety of ecologic, financial, and social reasons. Feasibility studies that evaluate whether a restoration effort should even be attempted can enhance restoration success by highlighting potential pitfalls and gaps in knowledge before the design phase of a restoration. Feasibility studies also can bring stakeholders together before a restoration project is designed to discuss potential disagreements. For these reasons, a feasibility study was conducted to evaluate the efficacy of restoring a tidal freshwater marsh in the Potomac River near Alexandria, Virginia. The study focused on science rather than engineering questions, and thus differed in approach from other feasibility studies that are mostly engineering driven. The authors report the framework they used to conduct a feasibility study to inform other potential restoration projects with similar goals. The seven steps of the framework encompass (1) initiation of a feasibility study, (2) compilation of existing data, (3) collection of current site information, (4) examination of case studies, (5) synthesis of information in a handbook, (6) meeting with selected stakeholders, and (7) evaluation of meeting outcomes. By conducting a feasibility study using the seven-step framework, the authors set the stage for conducting future compliance studies and enhancing the chance of a successful restoration. PMID:17453281

  17. Geothermal feasibility study for Malting Investments Inc

    SciTech Connect

    Not Available

    1981-10-01

    The engineering feasibility of using geothermal heat in the kilning, germination, and steep water cooling processes for a malting facility is determined. The study is based upon a malting facility with an annual capacity of malting three million bushels of clean graded barley per year or 8220 bushels per day. Capital cost figures used in the feasibility study are budget prices for the basic equipment only, they do not include any other costs such as installation, instrumentation or design and engineering costs. Utility prices are based upon $0.03 per kilowatt hour and $0.4548 per therm for natural gas.

  18. National estuary program guidance: Technical characterization in the National Estuary Program

    SciTech Connect

    Not Available

    1994-06-01

    Estuaries are waterways, such as bays and sounds, where fresh water drained from the surrounding watershed mixes with salt water from the ocean. Section 320 of the Clean Water Act established the National Estuary Program (NEP) to identify nationally significant estuaries threatened by pollution, development, or overuse and to promote the preparation of comprehensive management plans to ensure their ecological integrity. The program's goals are protection and improvement of water quality and enhancement of living resources. To reach these goals, the Administrator of the U.S. Environmental Protection Agency (EPA) convenes management conferences for each estuary in the NEP to provide a forum for consensus building and problem solving among interested agencies and user groups.

  19. PECONIC ESTUARY: AN ASSESSMENT OF SHELLFISH RESOURCES IN THE TRIBUTARIES AND EMBAYMENTS OF THE PECONIC ESTUARY

    EPA Science Inventory

    Executive Summary Historically, the Peconic Estuary's shellfish resources have supported significant fisheries for a number of species including hard clams, oysters and bay scallops. However, distribution and abundance data for the tributaries and embayments within the Peconic Es...

  20. In Brief: U.S. national estuaries in ``fair'' condition

    NASA Astrophysics Data System (ADS)

    Zielinski, Sarah

    2007-06-01

    The first report to evaluate the condition of the U.S. National Estuary Program finds that the 28 NEP estuaries are in ``fair condition'' and generally doing better or equal to non-NEP U.S. estuaries despite significant human population pressures. The estuaries were rated for water and sediment quality, benthic zone health, and fish tissue contaminants. NEP estuaries in the southeast received the highest ratings, and those in the northeast and Puerto Rico the lowest. The most common concerns for NEP estuaries include habitat loss and alteration, species loss and decline, nutrients, toxics, and pathogens. The ``National Estuary Program Coastal Condition Report'' is available at http://www.epa.gov/owow/oceans/nepccr/

  1. Historic Habitat Opportunities and Food-Web Linkages of Juvenile Salmon in the Columbia River Estuary, Annual Report of Research.

    SciTech Connect

    Bottom, Daniel L.; Simenstad, Charles A.; Campbell, Lance

    2009-05-15

    In 2002 with support from the U.S. Army Corps of Engineers (USACE), an interagency research team began investigating salmon life histories and habitat use in the lower Columbia River estuary to fill significant data gaps about the estuary's potential role in salmon decline and recovery . The Bonneville Power Administration (BPA) provided additional funding in 2004 to reconstruct historical changes in estuarine habitat opportunities and food web linkages of Columbia River salmon (Onchorhynchus spp.). Together these studies constitute the estuary's first comprehensive investigation of shallow-water habitats, including selected emergent, forested, and scrub-shrub wetlands. Among other findings, this research documented the importance of wetlands as nursery areas for juvenile salmon; quantified historical changes in the amounts and distributions of diverse habitat types in the lower estuary; documented estuarine residence times, ranging from weeks to months for many juvenile Chinook salmon (O. tshawytscha); and provided new evidence that contemporary salmonid food webs are supported disproportionately by wetland-derived prey resources. The results of these lower-estuary investigations also raised many new questions about habitat functions, historical habitat distributions, and salmon life histories in other areas of the Columbia River estuary that have not been adequately investigated. For example, quantitative estimates of historical habitat changes are available only for the lower 75 km of the estuary, although tidal influence extends 217 km upriver to Bonneville Dam. Because the otolith techniques used to reconstruct salmon life histories rely on detection of a chemical signature (strontium) for salt water, the estuarine residency information we have collected to date applies only to the lower 30 or 35 km of the estuary, where fish first encounter ocean water. We lack information about salmon habitat use, life histories, and growth within the long tidal-fresh reaches of the main-stem river and many tidally-influenced estuary tributaries. Finally, our surveys to date characterize wetland habitats within island complexes distributed in the main channel of the lower estuary. Yet some of the most significant wetland losses have occurred along the estuary's periphery, including shoreline areas and tributary junctions. These habitats may or may not function similarly as the island complexes that we have surveyed to date. In 2007 we initiated a second phase of the BPA estuary study (Phase II) to address specific uncertainties about salmon in tidal-fresh and tributary habitats of the Columbia River estuary. This report summarizes 2007 and 2008 Phase II results and addresses three principal research questions: (1) What was the historic distribution of estuarine and floodplain habitats from Astoria to Bonneville Dam? (2) Do individual patterns of estuarine residency and growth of juvenile Chinook salmon vary among wetland habitat types along the estuarine tidal gradient? (3) Are salmon rearing opportunities and life histories in the restoring wetland landscape of lower Grays River similar to those documented for island complexes of the main-stem estuary? Phase II extended our analysis of historical habitat distribution in the estuary above Rkm 75 to near Bonneville Dam. For this analysis we digitized the original nineteenth-century topographic (T-sheets) and hydrographic (H-sheets) survey maps for the entire estuary. Although all T-sheets (Rkm 0 to Rkm 206) were converted to GIS in 2005 with support for the USACE estuary project, final reconstruction of historical habitats throughout the estuary requires completion of the remaining H-sheet GIS maps above Rkm 75 and their integration with the T-sheets. This report summarizes progress to date on compiling the upper estuary H-sheets above Rkm 75. For the USACE estuary project, we analyzed otoliths from Chinook salmon collected near the estuary mouth in 2003-05 to estimate variability in estuary residence times among juvenile out migrants. In Phase II we expanded these analyses to compare growth and residency among individuals collected in tidal-fresh water wetlands of the lower main-stem estuary. Although no known otolith structural or chemical indicators currently exist to define entry into tidal fresh environments, our previous analyses indicate that otolith barium concentrations frequently increase before individuals encounter salt water. Here we evaluate whether otolith barium levels may provide a valid indicator of tidal fresh water entry by Columbia River Chinook salmon. We also examine otolith growth increments to quantify and compare recent (i.e., the previous 30 d) growth rates among individuals sampled in different wetland habitats along the estuarine tidal gradient.

  2. DPC loading feasibility study report

    SciTech Connect

    Dafoe, R.E.; Lopez, D.A.; Williams, K.L.

    1997-11-01

    Disposal of radioactive wastes now stored at the Idaho Chemical Processing Plant at the Idaho National Engineering and Environmental Laboratory is mandated under a ``Settlement Agreement`` between the Department of Energy and the State of Idaho. This study investigates the feasibility of using the Dry Transfer Cell facility to package waste into Dual Purpose Canisters for interim storage at the adjacent Dry Storage System comprised of an interim storage pad with NUHOMS{reg_sign} storage modules. The wastes would then be road-ready for eventual disposal in a permanent repository. The operating period for these activities is expected to be from 2015 to 2035.

  3. Assessment Of Sediment Trapping Efficiency In An Altered Estuary Through 210Pb And 137Cs Derived Accumulation Rates: Nakdong Estuary, South Korea

    NASA Astrophysics Data System (ADS)

    Williams, J. R.; Dellapenna, T. M.; Lee, G.

    2012-12-01

    Anthropogenic engineering within the last century of the coastal zone of Busan, South Korea has significantly affected the sedimentation dynamics within the Nakdong estuary. The construction of two estuarine dams (1934 and 1983) and numerous seawalls associated with land reclamation projects has altered the timing and flux of sediment and appreciably reduced the tidal prism. Consequently, vast geomorphologic changes have occurred including the development of several barrier islands. In order to assess the impacts of these modifications, 19 vibracores were obtained throughout the estuary. The dispersal and accumulation of sediment was evaluated utilizing radiochemical dating of 210Pb and 137Cs of 6 selected cores, X-radiographs of core sections, and laser diffraction particle size analyses. Average sediment accumulation rates range from 2.19 cm yr-1 adjacent to the first constructed dam, and were found to be as high as 6.55 cm yr-1 in the central portion of the estuary. These high rates are further supported by comparison of bathymetric survey data from 1985 to 2009. Analyses of grainsize, X-radiograph, and hydrographic data revealed distinctive changes associated with dam construction, and correlation of events between cores conveys the episodic sedimentation corresponding to flood gate releases. These data provide insight to the changes in sediment trapping efficiency that have ensued resulting from extensive coastal construction.

  4. BATHYMETRY FOR ALBEMARLE AND PAMLICO ESTUARIES, NC

    EPA Science Inventory

    Bathymetry for the Albemarle and Pamlico Estuaries obtained from National Oceanographic and Atmospheric Administration-National Ocean Service (NOAA-NOS). See the metadata within the files from NOAA-NOS for more details and warnings concerning merging with US Geolgoical Survey Dig...

  5. THE ECOLOGICAL CONDITION OF VERACRUZ, MEXICO ESTUARIES

    EPA Science Inventory

    During June and July, 2002, forty-seven stations were sampled within estuaries along the gulf coast of the state of Veracruz, MX, using a probabilistic survey design and a common set of response indicators. The objective of the study was to collect information to assess the condi...

  6. Listening to Estuary English in Singapore

    ERIC Educational Resources Information Center

    Deterding, David

    2005-01-01

    In Singapore, many people are not familiar with Estuary English (EE), the variety of English becoming popular in much of southern England. In the current study, when students listened to interviews with EE speakers and were asked to transcribe orthographically what they heard, most of them had severe problems. Features of pronunciation that

  7. Restoration of the Golden Horn Estuary (Halic).

    PubMed

    Coleman, Heather M; Kanat, Gurdal; Aydinol Turkdogan, F Ilter

    2009-12-01

    Restoration of the iconic Golden Horn Estuary in Istanbul, Turkey was a substantial political, logistical, ecological, and social challenge. Forty years of uncontrolled industrial and urban growth resulted in thick layers of anoxic sediment, toxic bacteria, strong hydrogen sulfide odor, and ecologically unlivable conditions. The major components of restoration, spanning two decades, have included (1) demolition and relocation of industries and homes along the shore, (2) creation of wastewater infrastructure, (3) removal of anoxic sludge from the estuary, (4) removal of a floating bridge that impeded circulation, and (5) creation of cultural and social facilities. Although Turkey is not known as an environmental leader in pollution control, the sum of these efforts was largely successful in revitalizing the area through dramatic water quality improvement. Consequently, the estuary is once again inhabitable for aquatic life as well as amenable to local resource users and foreign visitors, and Istanbul has regained a lost sense of cultural identity. This paper focuses on literature review and personal interviews to discuss the causes of degradation, solutions employed to rehabilitate the estuary, and subsequent physicochemical, ecological, and social changes. PMID:19781731

  8. MODELING FINE SEDIMENT TRANSPORT IN ESTUARIES

    EPA Science Inventory

    A sediment transport model (SEDIMENT IIIA) was developed to assist in predicting the fate of chemical pollutants sorbed to cohesive sediments in rivers and estuaries. Laboratory experiments were conducted to upgrade an existing two-dimensional, depth-averaged, finite element, coh...

  9. VOLUNTEER ESTUARY MONITORING: A METHOD MANUAL

    EPA Science Inventory

    Executive Summary: This manual focuses on volunteer estuary monitoring. As concern over the well-being of the environment has increased during the past couple of decades, volunteer monitoring has become an integral part of the effort to assess the health of our nations wat...

  10. TAMPA BAY ESTUARY PROGRAM, 2004 IMPLEMENTATION REVIEW

    EPA Science Inventory

    The Tampa Bay Estuary Program and its partners have made measurable progress toward implementation of the adopted CCMP goals. Progress has occurred in the following areas: bay habitats, with an increase in seagrass, estuarine habitat restoration and preservation; water and sedime...

  11. BCG Approaches for Improved Management of Estuaries

    EPA Science Inventory

    Estuaries and other complex aquatic systems are exposed to a variety of stressors that act at several scales, but are managed piecemeal - - often resulting in a death by 1000 cuts caused by cumulative impacts to these valued resources. To address this, managers need tools that...

  12. DELAWARE ESTUARY PROGRAM IMPLEMENTATION STREAMLINE REVIEW, 2002

    EPA Science Inventory

    The primary purpose of the Delaware Estuary Program implementation review (formerly known as the biennial review) has been to assist EPA in. making funding decisions for those NEPs that are in the post-CCMP, or implementation, phase, and to evaluate implementation progress. The i...

  13. INDICATORS OF ECOSYSTEM INTEGRITY FOR ESTUARIES

    EPA Science Inventory

    Jordan, Stephen J. and Lisa M. Smith. In press. Indicators of Ecosystem Integrity for Estuaries. In: Proceedings of the Estuarine Indicators Workshop, 29-31 October 2003, Sanibel Island, FL. Sanibel-Captiva Conservation Foundation, Sanibel, FL. 23 p. (ERL,GB 1194).

    Ideal ...

  14. Listening to Estuary English in Singapore

    ERIC Educational Resources Information Center

    Deterding, David

    2005-01-01

    In Singapore, many people are not familiar with Estuary English (EE), the variety of English becoming popular in much of southern England. In the current study, when students listened to interviews with EE speakers and were asked to transcribe orthographically what they heard, most of them had severe problems. Features of pronunciation that…

  15. Kaua'i: Streams and Estuaries.

    ERIC Educational Resources Information Center

    Hawkins, John, Ed.; Murakami, Colleen, Ed.

    Designed to help teachers develop students' awareness and understanding of some of Hawaii's endangered aquatic resources, this module contains activities and instructional suggestions for use with intermediate as well as high school students. The module is divided into two sections which explore the streams and estuaries of Kauai. Activities in…

  16. Estuaries and Tidal Marshes. Habitat Pac.

    ERIC Educational Resources Information Center

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    This educational packet consists of an overview, three lesson plans, student data sheets, and a poster. The overview examines estuaries and tidal or salt marshes by discussing the plants and animals in these habitats, marsh productivity, benefits and management of the habitats, historical aspects, and development and pollution. A glossary and list…

  17. Padilla Bay: The Estuary Guide. Level 2.

    ERIC Educational Resources Information Center

    Friesem, Judy; Lynn, Valerie, Ed.

    Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the middle school level is designed for use with the on-site program developed by the Padilla Bay National Esturine Research Reserve (Washington). The guide…

  18. Climate change and its impacts on estuaries

    EPA Science Inventory

    Past, present, and future research by WED scientists in the TEP region will be described to lay the foundation for examination of potential climate change effects on estuaries and the broader coastal zone in the Pacific Northwest (PNW). Results from National Coastal Assessments,...

  19. BCG Approaches for Improved Management of Estuaries

    EPA Science Inventory

    Estuaries and other complex aquatic systems are exposed to a variety of stressors that act at several scales, but are managed piecemeal - - often resulting in a “death by 1000 cuts” caused by cumulative impacts to these valued resources. To address this, managers need tools that...

  20. Baseline ecological risk assessment of the Calcasieu Estuary, Louisiana: 1. Overview and problem formulation

    USGS Publications Warehouse

    MacDonald, Donald D.; Moore, Dwayne R.J.; Ingersoll, Christopher G.; Smorong, Dawn E.; Carr, R. Scott; Gouguet, Ron; Charters, David; Wilson, Duane; Harris, Tom; Rauscher, Jon; Roddy, Susan; Meyer, John

    2011-01-01

    A remedial investigation/feasibility study (RI/FS) of the Calcasieu Estuary cooperative site was initiated in 1998. This site, which is located in the southwestern portion of Louisiana in the vicinity of Lake Charles, includes the portion of the estuary from the saltwater barrier on the Calcasieu River to Moss Lake. As part of the RI/FS, a baseline ecological risk assessment (BERA) was conducted to assess the risks to aquatic organisms and aquatic-dependent wildlife exposed to environmental contaminants. The purpose of the BERA was to determine if adverse effects on ecological receptors are occurring in the estuary; to evaluate the nature, severity, and areal extent of any such effects; and to identify the substances that are causing or substantially contributing to effects on ecological receptors. This article describes the environmental setting and site history, identifies the chemicals of potential concern, presents the exposure scenarios and conceptual model for the site, and summarizes the assessment and measurement endpoints that were used in the investigation. Two additional articles in this series describe the results of an evaluation of effects-based sediment-quality guidelines as well as an assessment of risks to benthic invertebrates associated with exposure to contaminated sediment.

  1. Nutrient budgets for large Chinese estuaries

    NASA Astrophysics Data System (ADS)

    Liu, S. M.; Hong, G.-H.; Zhang, J.; Ye, X. W.; Jiang, X. L.

    2009-10-01

    Chinese rivers deliver about 5-10% of global freshwater input and 15-20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon) in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN) and depleted in dissolved inorganic phosphate (PO43-) with very high DIN: PO43- concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3-4 times higher than those in the winter with the exception of NH4+. The flux of NH4+ is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state mass-balance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export <15% of nitrogen, <6% of phosphorus required for phytoplankton production and ~4% of silicon required for diatom growth in the Chinese Seas (Bohai, Yellow Sea, East China Sea, South China Sea). This suggests that land-derived nutrients are largely confined to the immediate estuaries, and ecosystem in the coastal sea beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and atmospheric deposition.

  2. A chemical survey of the Mississippi estuary

    SciTech Connect

    Fox, L.E.; Lipschultz, R.; Kerkhof, L.; Wofsy, S.C. )

    1987-03-01

    A snap shot survey of the Mississippi estuary was made during a period of low river discharge, when the estuarine mixing zone was within the deltaic channels. Concentrations of H{sup +}, Ca{sup 2+}, inorganic phosphorus and inorganic carbon suggest that the waters of the river and the low salinity (<5%) portion of the estuary are near saturation with respect to calcite and sedimentary calcium phosphate. An input of oxidized nitrogen species and N{sub 2}O was observed in the estuary between O and 4{per thousand} salinity. The concentrations of dissolved NH{sub 4}{sup +} and O{sub 2}, over most of the estuary, appeared to be influenced by decomposition of terrestrial organic matter in bottom sediments. The estuarine bottom also appears to be a source of CH{sub 4} which has been suggested to originate from petroleum shipping and refining operations. Estuarine mixing with offshore Gulf waters was the dominant influence on distributions of dissolved species over most of the estuary (i.e., from salinities > 5%). The phytoplankton abundance (measured as chlorophyll a) increased as the depth of the mixed layer decreased in a manner consistent with the expected for a light-limited ecosystem. Fluxes of NO{sub 3}{sup {minus}} + NO{sub 2}{sup {minus}} and soluble inorganic phosphorus to the Gulf of Mexico were estimated to be 3.4 {plus minus} 0.2 {times} 10{sup 3} g N s{sup {minus}1} and 1.9 {plus minus} g P s{sup {minus}1}, respectively, at the time of this study.

  3. Geophysical Assessment of the Control of a Jetty on a Barrier Beach and Estuary System

    NASA Astrophysics Data System (ADS)

    Ulrich, C.; Hubbard, S. S.; Peterson, J.; Blom, K.; Black, W.; Delaney, C.; Mendoza, J.

    2014-12-01

    An evaluation is underway at the Goat Rock State Park, located at the mouth of the Russian River near Jenner, CA, to quantify the influence of a man made jetty on the functioning of a barrier beach and associated implications for estuary fish habitat and flood control. Flow through the beach results from water level differences between the estuary and the ocean. When the estuary is closed or perched, one of the major sources of outflow from the lagoon is seepage flow through the barrier beach. The location and design of the jetty could be altering subsurface flow paths through the jetty and possibly impeding subsurface flow where the jetty is still intact. This will result in unnatural connectivity between the ocean and the estuary leading to atypical surface water elevations and possibly salinity imbalance. We are monitoring seepage through the jetty and beach berm with multiple surface and borehole geophysical methods, including: electrical resistivity (ERT), seismic refraction (SR), ground penetrating radar (GPR), and electromagnetic methods (EM). We use SR data to characterize deeper bedrock controls on beach barrier functioning; ERT and EM methods to characterize the beach sediment layers that could contribute to preferential flow paths during tide cycles in addition to preferential flow paths created by the jetty structure; time-lapse ERT and EM data to monitor moisture changes and mixing of saline and fresh water within the beach berm, and borehole ERT and GPR data to delineate the geometry of the (often buried) jetty. Preliminary ERT and EM results indicate two preferential flow paths through zones of missing jetty structure, while time-lapse borehole ERT data is expected to image saltwater flow impedance in zones of intact jetty structure. All data are being integrated with topography, tidal, borehole, and hydrological information and the results of the assessment will enable the Sonoma County Water Agency to develop the feasibility of alternatives to the existing jetty that may help achieve target estuarine water surface elevations.

  4. Geomorphologic and physical characteristics of a human impacted estuary: Quequn Grande River Estuary, Argentina

    NASA Astrophysics Data System (ADS)

    Perillo, Gerardo M. E.; Prez, Daniel E.; Piccolo, M. Cintia; Palma, Elbio D.; Cuadrado, Diana G.

    2005-01-01

    Even though the Quequn Grande River Estuary has economic and strategic importance from an oceanographic point of view, it has been ignored until recently. Nevertheless, many anthropogenic modifications (i.e., dredging, jetty and harbour construction, etc.) have taken place in the last 100 years which, most of them, have resulted in significative economic expenses to the harbour and city authorities due to the lack of adequate prior studies. The purpose of this article is to provide a review of the present status of the geomorphology and main physical characteristics of the estuary and describe the effects of these man-made modifications upon the estuary. Data were gathered in several field cruises from 1994 to 2000 plus from continuous recording devices installed at or near the estuary directed to define the present geomorphologic and oceanographic conditions of the estuary and to establish a monitoring program. The ultimate goal is to provide some practical solutions in diminishing the maintenance of the harbour and to provide pollution-control devices. The estuary is classified as a microtidal, primary, coastal-plain system. It can be considered as a partly-mixed system 2 km from the mouth up to its head (15 km inland). Artificial dredging to accommodate the Quequn harbour in the last 2 km of the estuary has induced a highly stratified water column where the upper 2-3 m concentrates low salinity water and the lower layer is filled by water of the same or slightly higher salinity than the inner shelf waters. Due to the presence of a step at the head of the harbour, water circulation is very reduced and in some cases nonexistent, producing strong reductive and even anoxic conditions. The foot of the step is a sediment and organic matter trap that must be dredged periodically to insure adequate navigability.

  5. 7 CFR 1980.442 - Feasibility studies.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... management, nature and extent of market area, marketing plans for sale of projected output, extent of... engineer or architect may be considered an independent party provided the principals of the firm or any individual of the firm who participates in the technical feasibility report does not have a...

  6. 7 CFR 1980.442 - Feasibility studies.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... management, nature and extent of market area, marketing plans for sale of projected output, extent of... engineer or architect may be considered an independent party provided the principals of the firm or any individual of the firm who participates in the technical feasibility report does not have a...

  7. Flow Liner Slot Edge Replication Feasibility Study

    NASA Technical Reports Server (NTRS)

    Newman, John A.; Willard, Scott A.; Smith, Stephen W.; Piascik, Robert S.

    2006-01-01

    Surface replication has been proposed as a method for crack detection in space shuttle main engine flowliner slots. The results of a feasibility study show that examination of surface replicas with a scanning electron microscope can result in the detection of cracks as small as 0.005 inch, and surface flaws as small as 0.001 inch, for the flowliner material.

  8. Historical changes in the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Sherwood, Christopher R.; Jay, David A.; Bradford Harvey, R.; Hamilton, Peter; Simenstad, Charles A.

    Historical changes in the hydrology, sedimentology, and physical oceanography of the Columbia River Estuary have been evaluated with a combination of statistical, cartographic, and numerical-modelling techniques. Comparison of data digitized from US Coast and Geodetic Survey bathymetric surveys conducted in the periods 1867-1875, 1926-1937, and 1949-1958 reveals that large changes in the morphology of the estuary have been caused by navigational improvements (jetties, dredged channels, and pile dikes) and by the diking and filling of much of the wetland area. Lesser changes are attributable to natural shoaling and erosion. There has been roughly a 15% decrease in tidal prism and a net accumulation of about 68 10 6m 3 of sediment in the estuary. Large volumes of sediment have been eroded from the entrance region and deposited on the continental shelf and in the balance of the estuary, contributing to formation of new land. The bathymetric data indicate that, ignoring erosion at the entrance, 370 to 485 10 6m 3 of sediment has been deposited in the estuary since 1868 at an average rate of about 0.5 cm y -1, roughly 5 times the rate at which sea level has fallen locally since the turn of the century. Riverflow data indicate that the seasonal flow cycle of the Columbia River has been significantly altered by regulation and diversion of water for irrigation. The greatest changes have occurred in the last thirty years. Flow variability over periods greater than a month has been significantly damped and the net discharge has been slightly reduced. These changes in riverflow are too recent to be reflected in the available in the available bathymetric data. Results from a laterally averaged, multiple-channel, two-dimensional numerical flow model (described in HAMILTON, 1990) suggest that the changes in morphology and riverflow have reduced mixing, increased stratification, altered the response to fortnightly (neap-spring) changes in tidal forcing, and decreased the salinity intrusion length and the transport of salt into the estuary. The overall effects of human intervention in the physical processes of the Columbia River Estuary (i.e. decrease in freshwater inflow, tidal prism, and mixing; increase in flushing time and fine sediment deposition, and net accumulation of sediment) are qualitatively similar to those observed in less energetic and more obviously altered estuarine systems. A concurrent reduction in wetland habitats has resulted in an estimated 82% reduction in emergent plant production and a 15% reduction in benthic macroalgae production, a combined production loss of 51,675 metric tons of organic carbon per year. This has been at least partially compensated by a large increase in the supply of riverine detritus derived from freshwater phytoplankton primary production. Comparison of modern and estimated preregulation organic carbon budgets for the estuary indicates a shift from a food web based on comparatively refractory macrodetritus derived from emergent vegetation to one involving more labile microdetritus derived from allochthonous phytoplankton. The shift has been driven by human-induced changes to the physical environment of the estuary. While this is a relatively comprehensive study of historical physical changes, it is incomplete in that the sediment budget is still uncertain. More precise quantification of the modern estuarine sediment budget will require both a better understanding of the fluvial input and dredging export terms and a sediment tranport model designed to explain historical changes in the sediment budget. Oceanographic studies to better determine the mechanisms leading to the formation of the turbidity maximum are also needed. The combination of cartography and modelling used in this study should be applicable in other systems where large changes in morphology have occurred in historical time.

  9. 78 FR 9887 - Proposed Information Collection; Comment Request; National Estuaries Restoration Inventory

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-12

    ... Estuaries Restoration Inventory AGENCY: National Oceanic and Atmospheric Administration (NOAA), Commerce... extension of a currently approved information collection. Collection of estuary habitat restoration project... to populate a restoration project database mandated by the Estuary Restoration Act of 2000....

  10. Second International Symposium on the Biogeochemistry of Model Estuaries: Estuarine processes in global change. Final report

    SciTech Connect

    Windom, H.L.

    1991-12-31

    This report summarizes estuary events discussed at the symposium on biogeochemistry. Topics include; sedimentation, salinity, inputs and outputs of the estuary, effects of global change, and the need for effective sampling and modeling of estuaries.

  11. Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, Annual Report 2010

    SciTech Connect

    Diefenderfer, Heida L.; Johnson, Gary E.; Sather, Nichole K.; Skalski, J. R.; Dawley, Earl M.; Coleman, Andre M.; Ostrand, Kenneth G.; Hanson, Kyle C.; Woodruff, Dana L.; Donley, Erin E.; Ke, Yinghai; Buenau, Kate E.; Bryson, Amanda J.; Townsend, Richard L.

    2011-10-01

    This report describes the 2010 research conducted under the U.S. Army Corps of Engineers (USACE) project EST-P-09-1, titled Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, and known as the 'Salmon Benefits' study. The primary goal of the study is to establish scientific methods to quantify habitat restoration benefits to listed salmon and trout in the lower Columbia River and estuary (LCRE) in three required areas: habitat connectivity, early life history diversity, and survival (Figure ES.1). The general study approach was to first evaluate the state of the science regarding the ability to quantify benefits to listed salmon and trout from habitat restoration actions in the LCRE in the 2009 project year, and then, if feasible, in subsequent project years to develop quantitative indices of habitat connectivity, early life history diversity, and survival. Based on the 2009 literature review, the following definitions are used in this study. Habitat connectivity is defined as a landscape descriptor concerning the ability of organisms to move among habitat patches, including the spatial arrangement of habitats (structural connectivity) and how the perception and behavior of salmon affect the potential for movement among habitats (functional connectivity). Life history is defined as the combination of traits exhibited by an organism throughout its life cycle, and for the purposes of this investigation, a life history strategy refers to the body size and temporal patterns of estuarine usage exhibited by migrating juvenile salmon. Survival is defined as the probability of fish remaining alive over a defined amount of space and/or time. The objectives of the 4-year study are as follows: (1) develop and test a quantitative index of juvenile salmon habitat connectivity in the LCRE incorporating structural, functional, and hydrologic components; (2) develop and test a quantitative index of the early life history diversity of juvenile salmon in the LCRE; (3) assess and, if feasible, develop and test a quantitative index of the survival benefits of tidal wetland habitat restoration (hydrologic reconnection) in the LCRE; and (4) synthesize the results of investigations into the indices for habitat connectivity, early life history diversity, and survival benefits.

  12. Interpreting the colour of an estuary

    NASA Astrophysics Data System (ADS)

    Bowers, D. G.; Evans, D.; Thomas, D. N.; Ellis, K.; Williams, P. J. le B.

    2004-01-01

    This paper explores the possibility of using water colour to quantify the concentration of coloured dissolved organic matter (CDOM), and through it, dissolved organic carbon (DOC) and salinity in a turbid estuary in which suspended sediments also influence water colour. The motivation of the work is that the method could be applied to water colour measurements made remotely from an aircraft (or, in larger estuaries, a satellite) enabling near-synoptic mapping of surface salinity and DOC distributions. The paper describes observations at 29 stations distributed along the salinity gradient of the Conwy estuary in North Wales. At each station, surface water samples were collected and analysed for salinity, concentrations of DOC, chlorophyll and suspended particles and absorption spectra of CDOM, or yellow substance. Profiles were made of both upwelling and downwelling irradiance in four narrow band channels, and these were used to calculate irradiance reflection and attenuation coefficients. Results show that spectrally averaged light absorption in the estuary is caused principally and equally by mineral suspended solids and yellow substance, with water and chlorophyll in third and fourth place. The CDOM is strongly correlated ( R2=0.99) in a negative sense with salinity, and more weakly correlated with DOC. There is a linear relationship between CDOM and the ratio of reflection coefficients in the red (670 nm) and blue-green (490 nm) parts of the spectrum, which could be applied to remote sensing; the slope and intercept of the relationship are however different to those found in less turbid water bodies. It is shown that the change in slope and intercept are consistent with the presence, in the Conwy estuary, of suspended particles which influence the water colour. A method is described and tested for inverting water colour measurements in a turbid estuary to give estimates of CDOM in the presence of suspended particles. The solution, which has not been adjusted to fit the data, produces profiles of CDOM, DOC and salinity, which behave reasonably but which currently have a limited accuracy. RMS differences between measured and optically derived parameters for the entire data set are 0.27 m -1 (CDOM), 4 PSU (salinity) and 67 ?M (DOC) although better accuracy is obtained on individual surveys. The fact that there is little bias between predicted and observed parameters indicates that much of the scatter is caused by random measurement error and that the approach is fundamentally sound.

  13. Iron isotope fractionation in subterranean estuaries

    NASA Astrophysics Data System (ADS)

    Rouxel, Olivier; Sholkovitz, Edward; Charette, Matthew; Edwards, Katrina J.

    2008-07-01

    Dissolved Fe concentrations in subterranean estuaries, like their river-seawater counterparts, are strongly controlled by non-conservative behavior during mixing of groundwater and seawater in coastal aquifers. Previous studies at a subterranean estuary of Waquoit Bay on Cape Cod, USA demonstrate extensive precipitation of groundwater-borne dissolved ferrous iron and subsequent accumulation of iron oxides onto subsurface sands. Waquoit Bay is thus an excellent natural laboratory to assess the mechanisms of Fe-isotope fractionation in redox-stratified environments and determine potential Fe-isotope signatures of groundwater sources to coastal seawater. Here, we report Fe isotope compositions of iron-coated sands and porewaters beneath the intertidal zone of Waquoit Bay. The distribution of pore water Fe shows two distinct sources of Fe: one residing in the upward rising plume of Fe-rich groundwater and the second in the salt-wedge zone of pore water. The groundwater source has high Fe(II) concentration consistent with anoxic conditions and yield ?56Fe values between 0.3 and -1.3. In contrast, sediment porewaters occurring in the mixing zone of the subterranean estuary have very low ?56Fe values down to -5. These low ?56Fe values reflect Fe-redox cycling and result from the preferential retention of heavy Fe-isotopes onto newly formed Fe-oxyhydroxides. Analysis of Fe-oxides precipitated onto subsurface sands in two cores from the subterranean estuary revealed strong ?56Fe and Fe concentration gradients over less than 2m, yielding an overall range of ?56Fe values between -2 and 1.5. The relationship between Fe concentration and ?56Fe of Fe-rich sands can be modeled by the progressive precipitation of Fe-oxides along fluid flow through the subterranean estuary. These results demonstrate that large-scale Fe isotope fractionation (up to 5) can occur in subterranean estuaries, which could lead to coastal seawater characterized by very low ?56Fe values relative to river values.

  14. An Ecosystem-Based Restoration Plan with Emphasis on Salmonid Habitats in the Lower Columbia River and Estuary

    SciTech Connect

    Johnson, Gary E.; Thom, Ronald M.; Whiting, Allan H.; Sutherland, George B.; Berquam, Taunja J.; Ebberts, Blaine; Ricci, Nicole M.; Southard, John A.; Wilcox, Jessica D.

    2003-10-14

    The Bonneville Power Administration (BPA), in coordination with the U. S. Army Corps of Engineers (COE) and NOAA Fisheries, originated this project (BPA Project No. 2002-076; Contract No. DE-AC06-76RL01830, Release No. 652-24). Their intent was to develop a useful habitat restoration plan for the lower Columbia River and estuary to help guide restoration efforts and fulfill Reasonable and Prudent Alternative Action 159 of the 2000 National Marine Fisheries Service Biological Opinion on operation of the Federal Columbia River Power System. This document focuses on salmon habitat, although its ecosystem-based approach necessarily affects other species as well. Salmon habitat restoration is best undertaken within the context of other biota and physical processes using an ecosystem perspective. The anticipated audience for the plan includes entities responsible for, interested in, or affected by habitat restoration in the lower Columbia River and estuary. Timeframes to apply this plan extend from the immediate (2003-2004) to the near-term (2005-2006) to the long-term (2007 and beyond). We anticipate and encourage that the plan be revised as new knowledge and experience are attained. A team comprised of the Columbia River Estuary Study Taskforce (CREST), the Lower Columbia River Estuary Partnership (Estuary Partnership), and Pacific Northwest National Laboratory (PNNL) wrote this document. The BPA and the COE, as the responsible Action Agencies, provided technical oversight. The Estuary Partnership's Science Work Group, NOAA Fisheries Habitat Conservation Division, Northwest Power Planning Council (NPPC) staff, and state and tribal fisheries management agencies reviewed drafts. The Independent Scientific Advisory Board of the NPPC reviewed and commented on the 90% draft. Revisions were incorporated into the final draft document subsequently released for public review. Extensive efforts were made to ensure a sound technical and policy basis and to solicit input from all interested parties.

  15. Small estuary, big port - progress in the management of the Stour-Orwell Estuary system

    NASA Astrophysics Data System (ADS)

    Spearman, Jeremy; Baugh, John; Feates, Nigel; Dearnaley, Mike; Eccles, Dan

    2014-10-01

    Management of port development is increasingly challenging because of the competitive requirement for deeper channels and because of the need to preserve important coastal wetlands which function as both habitat and flood defence. This paper describes the management of the Stour/Orwell Estuary system, Eastern England, an estuary system which has experienced considerable development and morphological change. The estuary is internationally important for its wetland bird populations and the intertidal areas of the estuary system are protected under European legislation. It is also the location of the Port of Felixstowe. In 1998/2000 the approach channel to the Port of Felixstowe was deepened from -12.5 mCD to -14.5 mCD. This paper describes the effects of the approach channel deepening, the approach taken to identifying the potential impact to intertidal habitat resulting from the deepening, the sediment recycling implemented as mitigation to prevent increased loss of habitat and the subsequent response of the estuary system to this intervention.

  16. A fully predictive model for salt intrusion in estuaries applied to the Yangtze estuary

    NASA Astrophysics Data System (ADS)

    Cai, Huayang; Savenije, Hubert H. G.; Zuo, Shuhua; Jiang, Chenjuan; Chua, Vivien P.

    2015-04-01

    Understanding the way the salinity distribution in an estuary reacts to external drivers (e.g., tide, fresh water discharge, dredging etc.) is important for both water quality and water resources management in estuaries. The salinity distribution depends strongly on the geometry of an estuary, but also on the fresh water discharge that counteracts the salt intrusion. In estuaries it is notoriously hard to estimate this discharge and subsequently to predict the parameters that determine the mixing behaviour depending on it. Recently a method has been developed to predict the fresh water discharge on the basis of water level observations. In addition predictive equations for tidal mixing have been updated and revised. In this paper, these two predictive methods are combined and subsequently applied to the Yangtze estuary under a wide variation of fresh water discharge. The predicted salt distribution appears to be in good agreement with observations. To provide insight into the optimum use of water resources (e.g., to determine the amount of fresh water discharge required to maintain a specific salt intrusion length), we further studied the salt intrusion pattern under different fresh water discharge conditions.

  17. Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India)

    NASA Astrophysics Data System (ADS)

    Shivaprasad, A.; Vinita, J.; Revichandran, C.; Reny, P. D.; Deepak, M. P.; Muraleedharan, K. R.; Naveen Kumar, K. R.

    2013-01-01

    The intratidal, spring-neap and seasonal variations in stratification were examined in the Cochin estuary. The observations established a strong connection with the distribution of chemical and biological properties. The influence of tides and river discharge forcing in water column stability was quantified using potential energy anomaly (PEA) and stratification parameter. Partially mixed (neap) and well-mixed (spring) conditions during low river discharge (dry) period were altered in monsoon by the salt wedge intrusions. The ecological impact of salt wedge propagation on high tides bringing upwelled water to the system was evident from the bottom hypoxic, high chlorophyll a and nutrient-rich conditions. Phosphate and nitrite concentrations were higher at the bottom saline conditions but silicate and nitrate were clearly supplied by river water. However, during ebb tide this front was driven out of the estuary. The periodic advance and retreat of the salt wedge was inevitable in making the system immune from extended hypoxia/anoxia and maintaining the health of the Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season. During monsoon, the intense flushing and reduction in salinity field expansion seemed to be responsible for the limited chlorophyll a levels along the surface of the Cochin estuary.

  18. Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India)

    NASA Astrophysics Data System (ADS)

    Shivaprasad, A.; Vinita, J.; Revichandran, C.; Reny, P. D.; Deepak, M. P.; Muraleedharan, K. R.; Naveen Kumar, K. R.

    2012-07-01

    The intratidal, spring-neap and seasonal variations in stratification were examined in Cochin estuary. The observations established a strong connection with the distribution of chemical and biological properties. The influence of tides and river discharge forcing in water column stability was quantified using potential energy anomaly (PEA) and stratification parameter. Partially mixed (neap) and well-mixed (spring) conditions during low river discharge (dry) period were altered in monsoon by the salt wedge intrusions. The ecological impact of salt wedge propagation on high tides bringing upwelled water to the system was evident from the bottom hypoxic, high chlorophyll a and nutrient-rich conditions. Phosphate and nitrite concentrations were higher at the bottom saline conditions but silicate and nitrate were clearly supplied by river water. However, during ebb tide this front was driven out of the estuary. The periodic advance and retreat of the salt wedge was inevitable in making the system immune from extended hypoxia/anoxia and maintaining the health of Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season. During monsoon, the intense flushing and reduction in salinity field expansion seemed to be responsible for the limited chlorophyll a levels along the surface of Cochin estuary.

  19. A predictive model for salt intrusion in estuaries applied to the Yangtze estuary

    NASA Astrophysics Data System (ADS)

    Cai, Huayang; Savenije, Hubert H. G.; Zuo, Shuhua; Jiang, Chenjuan; Chua, Vivien P.

    2015-10-01

    Understanding the way salinity distribution in an estuary reacts to external drivers (e.g., tide, fresh water discharge, dredging, etc.) is important for both water quality and water resources management in estuaries. The salinity distribution depends strongly on the geometry of an estuary, but also on the fresh water discharge that counteracts the salt intrusion. In estuaries it is notoriously hard to estimate this discharge and subsequently to predict the parameters that determine the mixing behaviour depending on it. Recently a method has been developed to predict the fresh water discharge on the basis of water level observations. In addition, predictive equations for tidal mixing have been updated and revised. In this paper, these two predictive methods are combined and subsequently applied to the Yangtze estuary under a wide variation of fresh water discharge. The predicted salt distribution appears to be in good agreement with observations. To provide insight into the optimum use of water resources (e.g., to determine the amount of fresh water discharge required to maintain a specific salt intrusion length), we further study the salt intrusion pattern under different tide and fresh water discharge conditions.

  20. Along-estuary dissolved oxygen variability in the Coos Bay estuary, Oregon, USA

    NASA Astrophysics Data System (ADS)

    O'Neill, M.; Sutherland, D.

    2013-12-01

    Hypoxia and anoxia are direct threats to the ecosystem and economic health of coastal communities. In estuaries, oceanic and terrestrial systems merge, making their relative influences on water properties such as dissolved oxygen (DO) difficult to tease apart. Recent studies show evidence for low DO conditions occurring on the Oregon shelf during the dry season on temporal and spatial scales unprecedented in the historic record. There is evidence now, too, showing that estuarine hypoxia, historically observed as a product mainly of terrestrial influences, is occurring due to the shifting properties of oceanic inputs. We report here on data collected in the Coos Bay estuary located on the southern Oregon coast, to quantify past and present DO levels to determine if hypoxia is occurring. We use monthly along-estuary sections of temperature, salinity, dissolved oxygen, turbidity, and fluorescence to examine the seasonal cycle of water properties. This data will be put into temporal context through analysis of historic data collected by state, federal, and private organizations. The goal is to link patterns in DO variation to the temporal and spatial circulation of water within the estuary. We show a significant along-estuary gradient in DO and discuss the variability of this gradient in time, over both seasonal and interannual scales.

  1. Benthic primary production in the Columbia River Estuary. Final report

    SciTech Connect

    McIntire, C.D.; Amspoker, M.C.

    1984-02-01

    The general objective of the research associated with the Benthic Primary Production Work Unit of Columbia River Estuary Development Program was to determine mechanisms that control the production dynamics and species composition of benthic plant assemblages in the Columbia River Estuary. In particular, the work was concerned with effects of selected physical variables on structural and functional attributes of micro- and macro- vegetation, and on the productivity and biomass of benthic autotrophs on the tidal flats of the estuary.

  2. Impact of climate change on Gironde Estuary

    NASA Astrophysics Data System (ADS)

    Laborie, Vanessya; Hissel, Franois; Sergent, Philippe

    2014-05-01

    Within the THESEUS European project, a simplified mathematical model for storm surge levels in the Bay of Biscay was adjusted on 10 events at Le Verdon using wind and pressure fields from CLM/SGA, so that the water levels at Le Verdon have the same statistic quantiles as observed tide records for the period [1960-2000]. The analysis of future storm surge levels shows a decrease in their quantiles at Le Verdon, whereas there is an increase of the quantiles of total water levels. This increase is smaller than the sea level rise and gets even smaller as one enters farther upstream in the estuary. A numerical model of the Gironde Estuary was then used to evaluate future water levels at 6 locations of the estuary from Le Verdon to Bordeaux and to assess the changes in the quantiles of water levels during the XXIst century using ONERC's pessimistic scenario for sea level rise (60 cm). The model was fed by several data sources : wind fields at Royan and Mrignac interpolated from the grid of the European Climatolologic Model CLM/SGA, a tide signal at Le Verdon, the discharges of Garonne (at La Role), the Dordogne (at Pessac) and Isle (at Libourne). A series of flood maps for different return periods between 2 and 100 years and for four time periods ([1960-1999], [2010-2039], [2040-2069] and [2070-2099]) have been built for the region of Bordeaux. Quantiles of water levels in the floodplain have also been calculated. The impact of climate change on the evolution of flooded areas in the Gironde Estuary and on quantiles of water levels in the floodplain mainly depends on the sea level rise. Areas which are not currently flooded for low return periods will be inundated in 2100. The influence of river discharges and dike breaching should also be taken into account for more accurate results.

  3. Migratory Behavior and Survival of Juvenile Salmonids in the Lower Columbia River and Estuary in 2009

    SciTech Connect

    McMichael, Geoffrey A.; Harnish, Ryan A.; Bellgraph, Brian J.; Carter, Jessica A.; Ham, Kenneth D.; Titzler, P. Scott; Hughes, Michael S.

    2010-08-01

    The study reported herein was funded as part of the Anadromous Fish Evaluation Program, which is managed by the U.S. Army Corps of Engineers (USACE). The Anadromous Fish Evaluation Program study code is EST P 02 01: A Study of Salmonid Survival and Behavior through the Columbia River Estuary Using Acoustic Tags. The study was conducted by the Pacific Northwest National Laboratory (PNNL) and National Oceanic and Atmospheric Administration (NOAA) Fisheries for the USACE Portland District. Estimated survival of acoustic-tagged juvenile Chinook salmon and steelhead through the lower Columbia River and estuary in 2009 was lowest in the final 50 km of the estuary. Probability of survival was relatively high (>0.90) for yearling and subyearling Chinook salmon from the Bonneville Dam forebay (rkm 236) to Three-tree Point (rkm 49.6). Survival of juvenile Chinook salmon declined sharply through the lower 50 km of the estuary. Acoustic-tagged steelhead smolts did not survive as well as juvenile Chinook salmon between Bonneville Dam and the mouth of the Columbia River. Steelhead survival began to decline farther upstream (at rkm 86) relative to that of the Chinook salmon stocks. Subyearling Chinook salmon survival decreased markedly as the season progressed. It remains to be determined whether later migrating subyearling Chinook salmon are suffering increasing mortality as the season progresses or whether some portion of the apparent loss is due to fish extending their freshwater residence. This study provided the first glimpse into what promises to be a very informative way to learn more about how juvenile salmonid passage experiences through the FCRPS may influence their subsequent survival after passing Bonneville Dam. New information regarding the influence of migration pathway through the lower 50 km of the Columbia River estuary on probability of survival of juvenile salmonids, combined with increased understanding regarding the foraging distances and time periods of avian predators should prove useful in developing or assessing management actions to reduce losses of juvenile salmonid smolts that attempt to pass through the estuary on their seaward migration.

  4. Tidal exchange between a freshwater tidal marsh and an impacted estuary: the Scheldt estuary, Belgium

    NASA Astrophysics Data System (ADS)

    Van Damme, Stefan; Frank, Dehairs; Micky, Tackx; Olivier, Beauchard; Eric, Struyf; Britta, Gribsholt; Oswald, Van Cleemput; Patrick, Meire

    2009-11-01

    Tidal marsh exchange studies are relatively simple tools to investigate the interaction between tidal marshes and estuaries. They have mostly been confined to only a few elements and to saltwater or brackish systems. This study presents mass-balance results of an integrated one year campaign in a freshwater tidal marsh along the Scheldt estuary (Belgium), covering oxygen, nutrients (N, P and Si), carbon, chlorophyll, suspended matter, chloride and sulfate. The role of seepage from the marsh was also investigated. A ranking between the parameters revealed that oxygenation was the strongest effect of the marsh on the estuarine water. Particulate parameters showed overall import. Export of dissolved silica (DSi) was more important than exchange of any other nutrient form. Export of DSi and import of total dissolved nitrogen (DIN) nevertheless contributed about equally to the increase of the Si:N ratio in the seepage water. The marsh had a counteracting effect on the long term trend of nutrient ratios in the estuary.

  5. Mercury biogeochemical cycling in a stratified estuary

    SciTech Connect

    Mason, R.P.; Fitzgerald, W.F. ); Hurley, J. ); Hanson, A.K. Jr.; Donaghay, P.L.; Sieburth, J.M. )

    1993-09-01

    Total Hg in the permanently stratified Pettaquamscutt estuary was <25 pM throughout the water column, even in highly sulfidic bottom waters. Particulate Hg was typically >40% of the total Hg. Reactive Hg (Hg[sub R]) was generally <3 pM and decreased with depth, but there is Hg[sub R] even in the anoxic bottom waters. Elemental Hg (Hg[sup 0]) was highest in the mixed layer and below the detection limit at depth. Demethylation is not an important source of Hg[sup 0] in this estuary. Dimethylmercury was not detected. Monomethylmercury (MMHg) was near the detection limit in the mixed layer and increased rapidly in the low oxygen region. Dissolved MMHg correlated with bacteriochlorophyll pigments, suggesting that the microbial community plays an important role in MMHg production in the estuary. The overall distributions of dissolved and particulate Hg species result from the interaction with Fe and Mn redox cycling, particulate scavenging and sinking, and MMHg production in the pycnocline. The estimated rate of MMHg production from Hg[sub R] in the pycnocline region is 1.7% d[sup [minus]1]. Hg[sup 0] and MMHg are formed principally in the mixed layer and in the pycnocline region, respectively. Particulate scavenging is important, and sedimentation, methylation, and Hg[sup 0] production are the principal sinks for Hg[sub R].

  6. Bottom fine sediment boundary layer and transport processes at the mouth of the Changjiang Estuary, China

    NASA Astrophysics Data System (ADS)

    Shi, John Z.; Zhang, S. Y.; Hamilton, L. J.

    2006-07-01

    SummaryImproved understanding of fine sediment transport processes within turbid estuaries has been of interest to both the coastal engineer and coastal oceanographer. The continuous measurement of fine suspended sediment concentration profiles is central to the study of transport processes. With this in mind, we utilise acoustic backscatter measurements to infer continuous vertical profiles of suspended sediment concentration. The acoustic profiling method has the advantage that it senses suspended sediment concentrations remotely and non-intrusively with a high degree of temporal and spatial resolution. Observational studies were undertaken to obtain more insight into the importance of bottom fine sediment boundary layer and transport processes to the seaward part of the North Passage in the Changjiang Estuary, China. Field measurements were made in October 1994 during spring, moderate and neap tides, respectively. Time series data of tidal elevations, current speed, and directions were measured. Vertical profiling of fine suspension concentration was made hourly by an acoustic suspended sediment monitor. Three dominant physical processes were identified: (1) the near-bed periodic resuspension by the tidal currents via tidal pumping; (2) the asymmetric stratifications due to fine suspension; and (3) the exchange of sediment between the bed and water column. The study also has its regional significance in estuarine morphodynamics, regulation of navigational channel, and water quality at the North Passage in the Changjiang Estuary.

  7. Freshwater, tidal and wave influences on a small estuary

    NASA Astrophysics Data System (ADS)

    Uncles, R. J.; Stephens, J. A.; Harris, C.

    2014-10-01

    Observations are presented of water levels, currents, salinity, turbidity, sediment grain sizes and sediment transport in the Devonshire Avon Estuary, UK, in order to improve knowledge of freshwater, wave and tidal influences on small, strongly tidal ra estuaries. A large reduction in tidal range occurred progressing from the coastal zone to the upper estuary that was mainly a consequence of rising bed and river water levels. The spring-neap cycle also had an influence on the reduction in tidal range along the length of the estuary. Surface gravity waves were completely dissipated propagating into the estuarine channel from the coastal zone, and despite strong wave-induced resuspension, suspended sediment was not transported into the lower estuary in observable amounts during the ensuing flood tide, indicating that the wave-suspended material was too coarse to remain in suspension once transported away from the surf zone. Turbidity in the lower estuary was relatively low during low runoff summer conditions and had largest values over low water, when turbid waters from farther up-estuary had been transported there. Strong resuspension events occurred at peak currents in the upper estuary during summer, reflecting the presence of finer-grained sediment sources. Turbidity was similar but greater in the lower estuary during high runoff winter conditions and strong resuspension occurred at peak currents, indicating an easily erodible, nearby sediment source, due to down-estuary movement and relocation of finer sediment over the winter. A large shoal in the lower estuary exhibited a consistent pattern of accretion/erosion during the high runoff months of late autumn and winter to spring that also was qualitatively consistent with sediment transport modelling and implied: (a), erosion from the up-estuary limit of the shoal with (b), down-estuary bed-load and suspended-load transport that accreted the centre and down-estuary limit of the shoal until (c), a diminished supply led to erosion via continued down-estuary transport from the shoal centre.

  8. 14-plex Feasibility Report

    SciTech Connect

    Kotongan, Victoria Hazel

    2013-06-21

    The Native Village of Unalakleet project was a feasibility study for a retrofit of a “tribally owned” three story, 14 apartment complex located in Unalakleet, Alaska. The program objective and overall goal was to create a plan for retrofitting to include current appraised value and comparable costs of new construction to determine genuine feasibility as low-income multi-family housing for tribal members.

  9. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2006

    SciTech Connect

    Johnson, Gary E.; Borde, Amy B.; Dawley, Earl; Diefenderfer, Heida L.; Ebberts, Blaine D.; Putman, Douglas A.; Roegner, G. C.; Thom, Ronald M.; Vavrinec, John; Whiting, Allan H.

    2007-12-06

    This report is the third annual report of a six-year project to evaluate the cumulative effects of habitat restoration action in the Columbia River Estuary (CRE). The project is being conducted for the U.S. Army Corps of Engineers (Corps) by the Marine Sciences Laboratory of the Pacific Northwest National Laboratory, the Pt. Adams Biological Field Station of the National Marine Fisheries Service, and the Columbia River Estuary Study Taskforce. Measurement of the cumulative effects of ecological restoration projects in the Columbia River estuary is a formidable task because of the size and complexity of the estuarine landscape and the meta-populations of salmonids in the Columbia River basin. Despite the challenges presented by this system, developing and implementing appropriate indicators and methods to measure cumulative effects is the best way to enable estuary managers to track the overall effectiveness of investments in estuarine restoration projects. This project is developing methods to quantify the cumulative effects of multiple restoration activities in the CRE. The overall objectives of the 2006 study were to continue to develop techniques to assess cumulative effects, refine the standard monitoring protocols, and initiate development of an adaptive management system for Corps of Engineers’ habitat restoration monitoring efforts in the CRE. (The adaptive management effort will be reported at a later date.) Field studies during 2006 were conducted in tidal freshwater at Kandoll Farm on the lower Grays River and tidal brackish water at Vera Slough on Youngs Bay. Within each of area, we sampled one natural reference site and one restoration site. We addressed the overall objectives with field work in 2006 that, coupled with previous field data, had specific objectives and resulted in some important findings that are summarized here by chapter in this report. Each chapter of the report contains data on particular monitored variables for pre- and post-restoration conditions at both the Kandoll and Vera study areas.

  10. Tide-driven fluid mud transport in the Ems estuary

    NASA Astrophysics Data System (ADS)

    Becker, Marius; Maushake, Christian; Winter, Christian

    2014-05-01

    The Ems estuary, located at the border between The Netherlands and Germany, experienced a significant change of the hydrodynamic regime during the past decades, as a result of extensive river engineering. With the net sediment transport now being flood-oriented, suspended sediment concentrations have increased dramatically, inducing siltation and formation of fluid mud layers, which, in turn, influence hydraulic flow properties, such as turbulence and the apparent bed roughness. Here, the process-based understanding of fluid mud is essential to model and predict mud accumulation, not only regarding the anthropogenic impact, but also in view of the expected changes of environmental boundary conditions, i.e., sea level rise. In the recent past, substantial progress has been made concerning the understanding of estuarine circulation and influence of tidal asymmetry on upstream sediment accumulation. While associated sediment transport formulations have been implemented in the framework of numerical modelling systems, in-situ data of fluid mud are scarce. This study presents results on tide-driven fluid mud dynamics, measured during four tidal cycles aside the navigation channel in the Ems estuary. Lutoclines, i.e., strong vertical density gradients, were detected by sediment echo sounder (SES). Acoustic Doppler current profiles (ADCP) of different acoustic frequencies were used to determine hydrodynamic parameters and the vertical distribution of suspended sediment concentrations in the upper part of the water column. These continuous profiling measurements were complemented by CTD, ADV, and OBS casts. SES and ADCP profiles show cycles of fluid mud entrainment during accelerating flow, and subsequent settling, and the reformation of a lutocline during decelerating flow and slack water. Significant differences are revealed between flood and ebb phase. Highest entrainment rates are measured at the beginning of the flood phase, associated with strong current shear and rapid vertical mixing, inducing the highest instantaneous suspended sediment flux measured during the tidal cycle. During decelerating flood currents a lutocline is again established at a certain distance above the consolidated river bed. During slack water after the flood phase the concentration gradient increases and the thickness of the fluid mud layer below is constant, also during a significant part of the ebb phase. As water depth decreases during ebb, entrainment occurs only at the upper part of the fluid mud layer. The suspended sediment flux is low compared to the flood phase. These observations are further elaborated using turbulence parameters obtained from ADV and ADCP, explaining the difference between ebb and flood concerning the vertical location of the maximum concentration gradient. This study is funded through DFG-Research Center / Excellence Cluster "The Ocean in the Earth System". The Senckenberg Institute and the Federal Waterways Engineering and Research Institute are acknowledged for technical support.

  11. Role and Value of Nitrogen Regulation Provided by Oysters (Crassostrea virginica) in the Mission-Aransas Estuary, Texas, USA

    PubMed Central

    Beseres Pollack, Jennifer; Yoskowitz, David; Kim, Hae-Cheol; Montagna, Paul A.

    2013-01-01

    Suspension-feeding activities of oysters impart a potentially significant benefit to estuarine ecosystems via reduction of water column nutrients, plankton and seston biomass, and primary productivity which can have a significant impact on human well-being. This study considered nitrogen regulation by eastern oysters Crassostrea virginica in the Mission-Aransas Estuary, Texas, USA, as a function of denitrification, burial, and physical transport from the system via harvest. Oyster reefs were estimated to remove 502.5 kg N km?2 through denitrification of biodeposits and 251.3 kg N km?2 in burial of biodeposits to sediments. Nitrogen is also physically transported out of the estuary via harvest of oysters. Commercial harvest of oysters in the Mission-Aransas Estuary can remove approximately 21,665 kg N per year via physical transport from the system. We developed a transferable method to value the service of nitrogen regulation by oysters, where the potential cost equivalent value of nitrogen regulation is quantified via cost estimates for a constructed biological nutrient removal (BNR) supplement to a wastewater treatment plant. The potential annual engineered cost equivalent of the service of nitrogen regulation and removal provided by reefs in the Mission-Aransas Estuary is $293,993 yr?1. Monetizing ecosystem services can help increase awareness at the stakeholder level of the importance of oysters beyond commercial fishery values alone. PMID:23762341

  12. The Oncor Geodatabase for the Columbia Estuary Ecosystem Restoration Program: Annual Report, 2012

    SciTech Connect

    Coleman, Andre M.; Johnson, Gary E.; Borde, Amy B.; Diefenderfer, Heida L.; Sather, Nichole K.; Seiple, Timothy E.; Serkowski, John A.

    2013-11-10

    Pacific Northwest National Laboratory (PNNL) conducted this project for the U.S. Army Corps of Engineers, Portland District (Corps). The purpose of the project is to develop a geospatial, web-accessible database (called “Oncor”) for action effectiveness and related data from monitoring and research efforts for the Columbia Estuary Ecosystem Restoration Program (CEERP). The intent is for the Oncor database to enable synthesis and evaluation, the results of which can then be applied in subsequent CEERP decision-making. This is the first annual report in what is expected to be a 3- to 4-year project, which commenced on February 14, 2012.

  13. ECOLOGICAL CONDITION OF ESTUARIES IN THE GULF OF MEXICO

    EPA Science Inventory

    The predominantly shallow estuaries in the Gulf of Mexico are ranked highest in the Nation in terms of water surface area, freshwater inflow, and wetlands area. Estuaries are an ecologically and economically valuable resource in the Gulf of Mexico. The U.S. Environmental Protecti...

  14. Identifying and organizing objectives across the 28 National Estuary Programs

    EPA Science Inventory

    The National Estuary Program (NEP), established in 1987 by amendments to the Clean Water Act, is intended to support local communities to restore, protect and manage estuaries of national significance. Currently there a 28 NEPs spread widely across the U.S. and its territories. E...

  15. INDEX OF ESTUARINE BENTHIC INTEGRITY FOR GULF OF MEXICO ESTUARIES

    EPA Science Inventory

    A benthic index for northern Gulf of Mexico estuaries has been developed and successfully validated by the Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) in the Louisianian Province. The benthic index is a useful indicator of estuarine condition that provi...

  16. FROM LANDSCAPE ECOLOGY OF WATERSHEDS TO BENTHIC ECOLOGY OF ESTUARIES

    EPA Science Inventory

    Do land use/cover characteristics of watersheds associated with small estuaries (<260 km2) have a strong enough signal to make landscape metrics useful for finding impaired bottom communities? We tested this idea with 58 pairs of small estuaries and watersheds from Delaware Bay t...

  17. LOWER COLUMBIA RIVER ESTUARY PROGRAM COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN

    EPA Science Inventory

    An estuary is the area where the fresh water of a river meets the salt water of an ocean. In the Columbia River system, this occurs in the lower 46 river miles. In an estuary, the river has a direct, natural connection with the open sea. This transition from fresh to salt water c...

  18. Trace metal concentrations in estuaries and coastal regions

    SciTech Connect

    Hunt, C.D.

    1994-12-31

    Estuaries and coastal regions are highly variable in the physical and hydrographic conditions. As a result of heavy urbanization and industrialization of the head waters of most estuaries, there are substantial localized inputs of contaminants to the estuary. These factors combined with the flushing characteristics of individual estuaries to create relatively unique features that result in variation in the typical levels of trace metals for these systems. This makes intercomparison of the estuaries difficult. Comparability among estuaries becomes even more difficult when metals analyses are conducted without proper control of field and laboratory contamination, now firmly established in the trace metal analytical literature as a prerequisite for reliable marine trace metals analysis. This paper compares the concentrations of selected trace metal (Ag, Cd, Cu, Ni, Pb, and Zn) concentrations in the waters of several major estuaries of the United States. The basis of comparison is that all samples war collected under rigid trace metal clean collection and analysis procedures. Generally, metal concentrations within the estuaries are similar. Metal concentrations in the higher salinity coastal regions are more similar in concentration. The comparison provides a baseline of typical concentrations of these trace metals in the coastal waters against which future analytical results can be compared.

  19. Nitrogen Source and Loading Data for EPA Estuary Data Mapper

    EPA Science Inventory

    Nitrogen source and loading data have been compiled and aggregated at the scale of estuaries and associated watersheds of the conterminous United States, using the spatial framework in EPA's Estuary Data Mapper (EDM) to provide system boundaries. Original sources of data include...

  20. ASSESSING THE ECOLOGICAL CONDITION OF SOUTHEAST U. S. ESTUARIES

    EPA Science Inventory

    As a means to assess ecological condition, 151 stations located in southeastern estuaries from Cape Henry, Virginia to Biscayne Bay, Florida were sampled by state agencies during the summer of 2000 using a probabilistic design. The design used 8 size classes of estuaries ranging ...

  1. Three dimensional water quality modeling of a shallow subtropical estuary.

    PubMed

    Wan, Yongshan; Ji, Zhen-Gang; Shen, Jian; Hu, Guangdou; Sun, Detong

    2012-12-01

    Knowledge of estuarine hydrodynamics and water quality comes mostly from studies of large estuarine systems. The processes affecting algae, nutrients, and dissolved oxygen (DO) in small and shallow subtropical estuaries are relatively less studied. This paper documents the development, calibration, and verification of a three dimensional (3D) water quality model for the St. Lucie Estuary (SLE), a small and shallow estuary located on the east coast of south Florida. The water quality model is calibrated and verified using two years of measured data. Statistical analyses indicate that the model is capable of reproducing key water quality characteristics of the estuary within an acceptable range of accuracy. The calibrated model is further applied to study hydrodynamic and eutrophication processes in the estuary. Modeling results reveal that high algae concentrations in the estuary are likely caused by excessive nutrient and algae supplies in freshwater inflows. While algal blooms may lead to reduced DO concentrations near the bottom of the waterbody, this study indicates that stratification and circulation induced by freshwater inflows may also contribute significantly to bottom water hypoxia in the estuary. It is also found that high freshwater inflows from one of the tributaries can change the circulation pattern and nutrient loading, thereby impacting water quality conditions of the entire estuary. Restoration plans for the SLE ecosystem need to consider both a reduction of nutrient loading and regulation of the freshwater discharge pattern. PMID:23122270

  2. PECONIC ESTUARY PROGRAM COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN

    EPA Science Inventory

    The Peconic Estuary, situated between the North and South Forks of eastern Long Island, New York, consists of more than 100 distinct bays, harbors, embayments, and tributaries. The area surrounding the Peconic Estuary's watershed is rich in rolling farmland, scenic beaches and cr...

  3. WATER QUALITY MODELING IN THE RIO CHONE ESTUARY

    EPA Science Inventory

    Water quality in the Rio Chone Estuary, a seasonally inverse, tropical estuary, in Ecuador was characterized by modeling the distribution of biochemical oxygen demand (BOD) and dissolved inorganic nitrogen (DIN) within the water column. These two variables are modeled using modif...

  4. Macroalgae, pore water sulfides and eelgrass in Yaquina estuary, Oregon

    EPA Science Inventory

    The hypothesis that relatively high nutrients in estuaries of the Pacific Northwest (PNW) can lead to eutrophication and degradation of critical eelgrass habitat was examined. Yaquina estuary was surveyed for cover and above-ground biomass of benthic macroalgae (Ulva spp.) and n...

  5. LIMNETIC LARVAL FISH OF THE MAUMEE AND SANDUSKY RIVER ESTUARIES

    EPA Science Inventory

    A total of 17 taxa were collected in the Maumee River estuary during sampling periods in 1975, 1976, and 1977. A total of 11 taxa were collected from the Sandusky River estuary in 1976. Gizzard shad/alewife, Dorosoma cepedianum/Alosa pseudoharengus, white bass/white perch, Morone...

  6. YAQUINA BAY AND BEYOND: WHAT SHAPE ARE OUR ESTUARIES IN?

    EPA Science Inventory

    The great natural beauty of Oregon's estuaries gives an impression of systems that are far less altered than those in other areas of the US. However, over the years, Yaquina Bay and other western estuaries have been variously affected by habitat loss and alteration, over harvest...

  7. PECONIC ESTUARY: RECREATIONAL AND RESOURCE ECONOMIC VALUES FOR THE PECONIC ESTUARY SYSTEM

    EPA Science Inventory

    The environmental and natural resources ("natural assets") of the Peconic Estuary System--the bay waters, beaches, wetlands, ecosystems, habitats, and parks and watershed lands--provide many services to the public. Outdoor recreation, scenic views, and the productivity of wetland...

  8. Approaches for Development of Nutrient Criteria in Oregon Estuaries With a Focus on Tillamook Estuary

    EPA Science Inventory

    Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

  9. The behavior of trace metals in the Geum Estuary, Korea

    SciTech Connect

    Byrd, J.T.; Smith, R.G.; Windom, H.L. ); Lee, Kwang, W. ); Lee, Dong, S. )

    1991-05-01

    The distributions of trace metals in the Geum Estuary of western Korea were studied with regard to changes in other estuarine chemical parameters. Dissolved oxygen, pH, and alkalinity increased with increasing salinity. Dissolved aluminum concentrations increased at low salinities and were perhaps influenced by the solubility of particulate aluminosilicate phases. Iron, manganese, cobalt, and zinc are removed from solution in the low salinity end of the estuary. Cobalt and nickel have mid-estuary concentration maxima that may be due to an anthropogenic source. Cadmium, copper, lead, and zinc concentrations also increased in the estuary, possibly as th result of remobilization in the sediments. Cadmium increases are also linked to remineralization from tidal flat sediments in the outer estuary. The source of an increase in dissolved lead at low salinity is unclear, but may be due to release from particles.

  10. United States Air Force 611th air support group, 611th Civil Engineer Squadron, Tin City Long Range Radar Station, Alaska final remedial investigation/feasibility study. Volume 1

    SciTech Connect

    1996-04-30

    This Final Remedial Investigation/Feasibility Study describes the work performed; explains project objectives; and presents data collected during project activities, results, and conclusions for the Installation Restoration Program at Tin City Longe Range Radar Station, Alaska. The report describes the risks posed by the site and gives the basis for selecting remedies to mitigate the risks.

  11. From the utilization point of view, the two approaches seem to United States Air Force 611th Air Support Group/Civil Engineering Squadron, Elmendorf AFB, Alaska. Remedial investigation and feasibility study Point Barrow Radar Installation, Alaska. Final report

    SciTech Connect

    Karmi, S.

    1996-02-19

    This report presents the findings of Remedial Investigations and Feasibility Studies at sites located at the Point Barrow radar installation in northern Alaska. The sites were characterized based on sampling and analyses conducted during Remedial Investigation activities performed during August and September 1993.

  12. United States Air Force 611th Air Support Group/Civil Engineering Squadron, Elmendorf AFB, Alaska. Remedial investigation and feasibility study: Oliktok Point Radar Installation, Alaska. Volume 1. (Includes appendices a - b)

    SciTech Connect

    1996-04-15

    This report presents the findings of Remedial Investigations and Feasibility Studies at sites located at the Oliktok Point radar installation in northern Alaska. The sites were characterized based on sampling and analyses conducted during Remedial Investigation activities performed during August and September 1993.

  13. Global patterns and predictors of fish species richness in estuaries.

    PubMed

    Vasconcelos, Rita P; Henriques, Sofia; Frana, Susana; Pasquaud, Stphanie; Cardoso, Ins; Laborde, Marina; Cabral, Henrique N

    2015-09-01

    1. Knowledge of global patterns of biodiversity and regulating variables is indispensable to develop predictive models. 2. The present study used predictive modelling approaches to investigate hypotheses that explain the variation in fish species richness between estuaries over a worldwide spatial extent. Ultimately, such models will allow assessment of future changes in ecosystem structure and function as a result of environmental changes. 3. A comprehensive worldwide data base was compiled of the fish assemblage composition and environmental characteristics of estuaries. Generalized Linear Models were used to quantify how variation in species richness among estuaries is related to historical events, energy dynamics and ecosystem characteristics, while controlling for sampling effects. 4. At the global extent, species richness differed among marine biogeographic realms and continents and increased with mean sea surface temperature, terrestrial net primary productivity and the stability of connectivity with a marine ecosystem (open vs. temporarily open estuaries). At a smaller extent (within a marine biogeographic realm or continent), other characteristics were also important in predicting variation in species richness, with species richness increasing with estuary area and continental shelf width. 5. The results suggest that species richness in an estuary is defined by predictors that are spatially hierarchical. Over the largest spatial extents, species richness is influenced by the broader distributions and habitat use patterns of marine and freshwater species that can colonize estuaries, which are in turn governed by history contingency, energy dynamics and productivity variables. Species richness is also influenced by more regional and local parameters that can further affect the process of community colonization in an estuary including the connectivity of the estuary with the adjacent marine habitat, and, over smaller spatial extents, the size of these habitats. In summary, patterns of species richness in estuaries across large spatial extents seem to reflect from global to local processes acting on community colonization. The importance of considering spatial extent, sampling effects and of combining history and contemporary environmental characteristics when exploring biodiversity is highlighted. PMID:25788236

  14. PECONIC ESTUARY: AN INVENTORY OF SUBMERGED AQUATIC VEGETATION AND HARDENED SHORELINES FOR THE PECONIC ESTUARY, NEW YORK

    EPA Science Inventory

    Executive Summary The Peconic Estuary Program (PEP) is interested in the extent of eelgrass and other submerged aquatic vegetation and in documenting changes in the shorelines of the Peconic Estuary. The Suffolk County Department of Health Services' Office of Ecology provided fun...

  15. AN APPROACH TO DEVELOPING NUTRIENT CRITERIA FOR PACIFIC NORTHWEST ESTUARIES: A CASE STUDY OF YAQUINA ESTUARY, OREGON

    EPA Science Inventory

    NHEERL scientists have developed an approach that could be used by the State of Oregon for development of nutrient and other water quality criteria for the Yaquina Estuary, Oregon. The principle objective in setting protective criteria is to prevent future degradation of estuari...

  16. Ecological Engineering Practices for the Reduction of Excess Nitrogen in Human-Influenced Landscapes: A Guide for Watershed Managers

    EPA Science Inventory

    Excess nitrogen (N) in freshwater systems, estuaries, and coastal areas has well-documented deleterious effects on ecosystems. Ecological engineering practices (EEPs) may be effective at decreasing nonpoint source N leaching to surface and groundwater. However, few studies have s...

  17. Latest Holocene evolution and human disturbance of a channel segment in the Hudson River Estuary

    USGS Publications Warehouse

    Klingbeil, A.D.; Sommerfield, C.K.

    2005-01-01

    The latest Holocene sedimentary record of a cohesive channel and subtidal shoal in the lower Hudson River Estuary was examined to elucidate natural (sea-level rise, sediment transport) and anthropogenic (bulkheading, dredging) influences on the recent morphodynamic evolution of the system. To characterize the seafloor and shallow subbottom, ??? 100 km of high-resolution seismic reflection profiles (chirp) were collected within a 20-km reach of the estuary and correlated with sediment lithologies provided by eight vibracores recovered along seismic lines. Sediment geochronology with 137Cs and 14C was used to estimate intermediate and long-term sedimentation rates, respectively, and historical bathymetric data were analyzed to identify regional patterns of accretion and erosion, and to quantify changes in channel geometry and sediment volume. The shoal lithosome originated around 4 ka presumably with decelerating eustatic sea level rise during the latest Holocene. Long-term sedimentation rates on the shoal (2.3-2.6 mm/yr) are higher than in the channel (2 mm/yr) owing to hydrodynamic conditions that preferentially sequester suspended sediment on the western side of the estuary. As a result, the shoal accretes oblique to the principal axis of tidal transport, and more rapidly than the channel to produce an asymmetric cross-section. Shoal deposits consist of tidally bedded muds and are stratified by minor erosion surfaces that seismic profiles reveal to extend for 10s of meters to kilometers. The frequency and continuity of these surfaces suggest that the surficial shoal is catastrophically stripped on decadal-centennial time scales by elevated tidal flows; tidal erosion maintains the shoal at a uniform depth below sea level and prevents it from transitioning to an intertidal environment. Consequently, the long-term sedimentation rate approximates the rate of sea-level rise in the lower estuary (1-3 mm/yr). After the mid 1800s, the natural geometry of the lower Hudson River Estuary changed rapidly in response to engineering works that forced the channel to self-deepen. Analysis of historical bathymetric data indicates that the channel lost an estimated 3 ?? 106 tons of sediment between ca. 1939 and 2002 (50,000 tons/yr average) by subaqueous erosion, increasing in depth by as much as 4 m in places. Erosion appears to have been concurrent with systematic bulkheading of the shoreline after ca. 1865, which decreased the estuary surface area by ??? 19% overall. Evidently, self-deepening of the channel is a morphodynamic adjustment to reestablish equilibrium cross-sectional area, yet the state of this change locally and elsewhere in the estuary is unknown. Subaqueous erosion documented in this study is a significant source of sediment with implications to the sediment budget and environmental quality of the Hudson River Estuary. ?? 2005 Elsevier B.V. All rights reserved.

  18. Phosphorous dynamics in a temperate intertidal estuary

    NASA Astrophysics Data System (ADS)

    Lilleb, A. I.; Neto, J. M.; Flindt, M. R.; Marques, J. C.; Pardal, M. A.

    2004-09-01

    Conservation and management of aquatic systems require detailed information of the processes that affect their functioning and development. The objectives of the present work were to describe the phosphorus dynamics during a complete tidal cycle and to quantify the relative contribution of the most common estuarine areas (e.g. seagrass beds, salt marshes, mud- and sand-flats without vegetation) to phosphorus net internal loading in a temperate intertidal estuary. Results show that phosphate efflux rates were higher during the first hours of tidal flood, and that phosphate concentrations were lowest at high tide. During tidal ebbing, ephemeral tide pools may cover a considerable percentage of the intertidal area. In these tide pools, water shallowness combined with enhanced temperatures stimulate the occurrence of high phosphate effluxes. The effluxes to the main water body during high tide contributed 57% of dissolved inorganic phosphorus and efflux during low tide contributed 43% to the net internal loading. Calculations of the phosphate net effluxes (kg P) indicate a strong contribution of the bare bottom mud-flats to the whole system internal phosphate loading, especially during the warmer periods. As a consequence of eutrophication, perennial benthic macrophytes are commonly replaced by fast-growing epiphytic macroalgae. Calculations showed that for a hypothetical intertidal estuary in a temperate region, management programs considering an eventual re-colonization of mud-flats by seagrasses or salt marsh plants may reduce the P-efflux by 13-16 kg ha -1. For example, in the small Mondego estuary, eutrophication has contributed to a reduction of the Zostera noltii meadows, leading to an increase in 190 kg of phosphorus net internal loading.

  19. Near coastal program plan for 1991: Estuaries

    SciTech Connect

    Not Available

    1990-11-01

    Environmental regulatory programs in the United States have been estimated to cost more than $70 billion annually. The Environmental Monitoring and Assessment Program (EMAP) is a nationwide initiative being implemented by EPA's Office of Research and Development (ORD). It was developed in response to the demand for information on the condition of the nation's ecological resources. The goal of EMAP is to assess and document the status and trends in the condition of the nation's forests, wetlands, estuaries, coastal waters, lakes, rivers, and streams, Great Lakes, agricultural lands, and arid lands on an integrated and continuing basis.

  20. The estuary part of low-inflow estuaries: stratification and residence in a Tomales Bay tributary estuary.

    NASA Astrophysics Data System (ADS)

    Abe, R. M.; Largier, J.

    2008-12-01

    Flow continues in Lagunitas Creek throughout the summer, delivering freshwater to the hypersaline Tomales Bay estuary. The freshwater-saltwater interface is found in the narrow estuarine channel that connects the creek and the bay, with minimal freshwater influence being found seaward of the broad shallow deltaic region at the head of the deeper sections of Tomales Bay. Observations of salinity, temperature, waterlevel and dissolved oxygen describe a stratified system, interrupted by mixing during flood tides. Denser waters are trapped in deeper sections of the estuary, but only transiently. The estuarine channel is about 3km long and constrained by dykes used to convert salt-marshes to agricultural lands. These dykes are now being removed to allow restoration of over 500 acres of salt-marsh in the vicinity of the study region. Longitudinal surveys were conducted and moored sensors were deployed to obtain a detailed view of tidal variations. Estimates of vertical and horizontal mixing, as well as residence times, will be compared with results from a post-restoration study to assess the impacts of restoration on the pelagic estuarine environment.

  1. Change in Land Cover along the Lower Columbia River Estuary as Determined from Landsat Thematic Mapper (TM) Imagery, Technical Report 2003.

    SciTech Connect

    Garono, Ralph; Anderson, Becci; Robinson, Rob

    2003-10-01

    The Lower Columbia River Estuary Management Plan (Jerrick, 1991) recognizes the positive relationship between the conservation of fish and wildlife habitat, and sustaining their populations. An important component of fish and wildlife conservation and management is the identification of habitats, trends in habitat change, and delineation of habitat for preservation, restoration or enhancement. Alterations to the environment, such as hydropower generation, dredging, forestry, agriculture, channel alteration, diking, bank stabilization and floodplain development, have dramatically altered both the type and distribution of habitats along the Columbia River Estuary (CRE) and its floodplain. Along the Columbia River, tidally influenced habitats occur from the river mouth to the Bonneville Dam, a distance of 230 km. If we are to effectively manage the natural resources of the Columbia River ecosystem, there is a need to understand how habitats have changed because fish and wildlife populations are known to respond to changes in habitat quality and distribution. The goal of this study was to measure the amount and type of change of CRE land cover from 1992 to 2000. We performed a change analysis on two spatial data sets describing land cover along the lower portion of the estuary (Fig. 1). The 1992 data set was created by the NOAA Coastal Remote Sensing, Coastal Change Analysis Program (C-CAP) in cooperation with Columbia River Estuary Study Task Force (CREST), the National Marine Fisheries Service (NMFS) Point Adams Field Station, and State of Washington Department of Natural Resources (DNR). The 2000 data set was produced by Earth Design Consultants, Inc. (EDC) and the Wetland Ecosystem Team (WET: University of Washington) as part of a larger Lower Columbia River Estuary Partnership (Estuary Partnership) habitat mapping study. Although the image classification methodologies used to create the data sets differed, both data sets were produced by classifying Landsat Thematic Mapper (TM) satellite imagery, making it feasible to assess land cover changes between 1992 and 2000.

  2. Facilitation of the Estuary/Ocean Subgroup and the Expert Regional Technical Group, Annual Report for 2015

    SciTech Connect

    Johnson, Gary E.

    2015-08-01

    This document is the annual report for the period September 1, 2014 through August 31, 2015 for the project—Facilitation of the Estuary/Ocean Subgroup (EOS) and the Expert Regional Technical Group (ERTG). Pacific Northwest National Laboratory (PNNL) conducted the project for the Bonneville Power Administration (BPA). The EOS and ERTG are part of the research, monitoring, and evaluation (RME) and habitat restoration efforts, respectively, developed by the Action Agencies (BPA, U.S. Army Corps of Engineers [Corps or USACE], and U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS) and implemented under the Columbia Estuary Ecosystem Restoration Program (CEERP). BPA/Corps (2015) explain the CEERP and the role of RME and the ERTG. For the purposes of this report, the lower Columbia River and estuary (LCRE) includes the floodplain from Bonneville Dam down through the lower river and estuary into the river’s plume in the ocean. The main purpose of this project is to facilitate EOS and ERTG meetings and work products. Other purposes are to provide technical support for CEERP adaptive management, CEERP restoration design challenges, and tributary RME. From 2002 through 2008, the EOS worked to design the federal RME program for the estuary/ocean (Johnson et al. 2008). From 2009 to the present day, EOS activities have involved RME implementation; however, EOS activities were minimal during the current reporting period. PNNL provided technical support to CEERP’s adaptive management process by convening 1.2 meetings of the Action Agencies (AAs) and drafting material for the “CEERP 2015 Restoration and Monitoring Plan” (BPA/Corps 2015).

  3. Development of a Hydrodynamic Model for Skagit River Estuary for Estuarine Restoration Feasibility Assessment

    SciTech Connect

    Yang, Zhaoqing; Liu, Hedong; Khangaonkar, Tarang P.

    2006-08-03

    The Skagit River is the largest river in the Puget Sound estuarine system. It discharges about 39% of total sediment and more than 20% of freshwater into Puget Sound. The Skagit River delta provides rich estuarine and freshwater habitats for salmon and many other wildlife species. Over the past 150 years, economic development in the Skagit River delta has resulted in significant losses of wildlife habitat, particularly due to construction of dikes. Diked portion of the delta is known as Fir Island where irrigation practices for agriculture land over the last century has resulted in land subsidence. This has also caused reduced efficiency of drainage network and impeded fish passages through the area. In this study, a three-dimensional tidal circulation model was developed for the Skagit River delta to assist estuarine restoration in the Fir Island area. The hydrodynamic model used in the study is the Finite Volume Coastal Ocean Model (FVCOM). The hydrodynamic model was calibrated using field data collected from the study area specifically for the model development. Wetting and drying processes in the estuarine delta are simulated in the hydrodynamic model. The calibrated model was applied to simulate different restoration alternatives and provide guidance for estuarine restoration and management. Specifically, the model was used to help select and design configurations that would improve the supply of sediment and freshwater to the mudflats and tidal marsh areas outside of diked regions and then improve the estuarine habitats for salmon migration.

  4. Educational Feasibility Study -- 1966.

    ERIC Educational Resources Information Center

    Hubbard, Ben C., Comp.; And Others

    By virtue of a Title III Elementary and Secondary Education Act grant, the feasibility of consolidating 7 Illinois high schools was studied. Areas of consideration were geographic characteristics, high school and elementary curriculum, and cost considerations relative to high school and elementary school buildings, curriculum, transportation,…

  5. Educational Feasibility Study -- 1966.

    ERIC Educational Resources Information Center

    Hubbard, Ben C., Comp.; And Others

    By virtue of a Title III Elementary and Secondary Education Act grant, the feasibility of consolidating 7 Illinois high schools was studied. Areas of consideration were geographic characteristics, high school and elementary curriculum, and cost considerations relative to high school and elementary school buildings, curriculum, transportation,

  6. Mercury distribution in Douro estuary (Portugal).

    PubMed

    Ramalhosa, E; Pereira, E; Vale, C; Vlega, M; Monterroso, P; Duarte, A C

    2005-11-01

    Determinations of dissolved reactive and total dissolved mercury, particulate and sedimentary mercury, dissolved organic carbon (DOC), particulate organic carbon (POC) and suspended particulate matter (SPM) have been made in the estuary of river Douro, in northern Portugal. The estuary was stratified by salinity along most of its length, it had low concentrations of SPM, typically <20 mg dm(-3), and concentrations of DOC in the range <1.0-1.8 mg dm(-3). The surface waters had a maximum dissolved concentration of reactive mercury of about 10 ng dm(-3), whereas for the more saline bottom waters it was about 65 ng dm(-3). The surface waters had maximum concentrations of total suspended particulate mercury of approximately 7 microg g(-1) and the bottom waters were always <1 microg g(-1). Concentrations of mercury in sediments was low and in the range from 0.06 to 0.18 microg g(-1). The transport of mercury in surface waters was mainly associated with organic-rich particulate matter, while in bottom waters the dissolved phase transport of mercury is more important. Lower particulate organic matter, formation of chlorocomplexes in more saline waters and eventually the presence of colloids appear to explain the difference of mercury partitioning in Douro estuarine waters. PMID:15893331

  7. Occurrence of juvenile Japanese flounder Paralichthys olivaceus in brackish estuaries

    NASA Astrophysics Data System (ADS)

    Tomiyama, Takeshi; Yamashita, Yoh; Tanaka, Masaru

    2009-12-01

    Juvenile Japanese flounder Paralichthys olivaceus usually inhabit high salinity inshore sandy areas. In June-August 1997, 25 individuals of juvenile Japanese flounder (33-75 mm total length) were collected in the Natori and Nanakita River estuaries in Sendai Bay, Japan. This is the first record of this species being collected in brackish estuaries in which salinities fluctuate from 0 to 30 over a spring tidal cycle. Factors of rainfall, river flow, or year class strength of Japanese flounder were unable to explain the unusual occurrence of this species in the estuaries. The collected juvenile Japanese flounder were considered to have migrated into the estuaries around the time of the passage of an unusually early typhoon that affected this area, indicating the possibility that this species utilizes estuaries for refuge from strong disturbance in its usual habitats. The juveniles fed mainly upon mysids both in the estuaries and the sandy beach area, indicating that estuaries can be a substitute nursery habitat for this species.

  8. Scavenging Rate Ecoassay: A Potential Indicator of Estuary Condition

    PubMed Central

    Porter, Augustine G.; Scanes, Peter R.

    2015-01-01

    Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress. PMID:26024225

  9. Geographic signatures of North American West Coast estuaries

    USGS Publications Warehouse

    Emmett, Robert; Llansó, Roberto; Newton, Jan; Thom, Ron; Hornberger, Michelle; Morgan, Cheryl; Levings, Colin; Copping, Andrea; Fishman, Paul

    2000-01-01

    West Coast estuaries are geologically young and composed of a variety of geomorphological types. These estuaries range from large fjords to shallow lagoons; from large to low freshwater flows. Natural hazards include E1 Niños, strong Pacific storms, and active tectonic activity. West Coast estuaries support a wide range of living resources: five salmon species, harvestable shellfish, waterfowl and marine birds, marine mammals, and a variety of algae and plants. Although populations of many of these living resources have declined (salmonids), others have increased (marine mammals). West Coast estuaries are also centers of commerce and increasingly large shipping traffic. The West Coast human population is rising faster than most other areas of the U.S. and Canada, and is distributed heavily in southern California, the San Francisco Bay area, around Puget Sound, and the Fraser River estuary. While water pollution is a problem in many of the urbanized estuaries, most estuaries do not suffer from poor water quality. Primary estuarine problems include habitat alterations, degradation, and loss; diverted freshwater flows; marine sediment contamination; and exotic species introductions. The growing West Coast economy and population are in part related to the quality of life, which is dependent on the use and enjoyment of abundant coastal natural resources.

  10. Organic matter and nutrient inputs to the Humber Estuary, England.

    PubMed

    Boyes, Suzanne; Elliott, Michael

    2006-01-01

    Estuaries are sinks for organic matter and nutrients entering both from their catchments and also from the adjacent lands and urban areas and in turn they are sources of such materials to the adjacent coast. The present paper quantifies the relative amounts of natural and anthropogenic organic matter and nutrients entering the Humber Estuary, Eastern England, including the allochthonous and autochthonous materials, those from urban and industrial sewage and from the catchment drainage of arable land. These data thus give a budget for the estuary which in turn answers questions fundamental to the management of the estuary. The estimations within the study have been carried out against a background of designating estuaries under the European Union Urban Waste-water Treatment Directive and the EU Nitrates Directive. The assessment has particularly addressed the question, related to the former Directive, of whether the Humber Estuary is eutrophic or likely to become eutrophic unless management measures are taken. Thus the paper indicates the nature and value of control measures such as treatment plant upgrading and the designation of Nitrate Vulnerable Zones. The paper includes the recent national and European discussions on the designation of areas under these Directives. Finally, the study has allowed a quantification of the present organic inputs to the estuary in comparison to those entering prior to large scale land-claim which had removed natural organic-producing wetlands. PMID:16256145

  11. Scavenging rate ecoassay: a potential indicator of estuary condition.

    PubMed

    Porter, Augustine G; Scanes, Peter R

    2015-01-01

    Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress. PMID:26024225

  12. Distribution and assessment of sediment toxicity in Tamaki Estuary, Auckland, New Zealand

    NASA Astrophysics Data System (ADS)

    Abrahim, G. M. S.; Parker, R. J.; Nichol, S. L.

    2007-07-01

    Heavy metal levels in surface sediments from Tamaki Estuary demonstrate significant up estuary increases in Cu, Pb, Zn, Cd and mud concentrations. Increased metal levels towards the head of the estuary are linked to local catchment sources reflecting the historical development, industrialisation and urbanisation of catchment areas surrounding the upper estuary. The relatively narrow constriction in the middle estuary (Panmure area), makes it susceptible to accumulation of upper estuary pollutants, since the constriction reduces circulation and extends the time required for fine waterborne sediments in the upper estuary to exchange with fresh coastal water. As a result fine fraction sediments trapped in the upper estuary facilitate capture and retention of pollutants at the head of the estuary. The increase in sandy mud poor sediments towards the mouth of the estuary is associated with generally low metal concentrations. The estuarys geomorphic shape with a mid estuary constriction, sediment texture and mineralogy and catchment history are significant factors in understanding the overall spatial distribution of contaminants in the estuary. Bulk concentration values for Cu, Pb, Zn, and Cd in all the studied surface samples occur below ANZECC ISQG-H toxicity values. Cd and Cu concentrations are also below the ISQG-L toxicity levels for these elements. However, Pb and Zn concentrations do exceed the ISQG-L values in some of the surface bulk samples in the upper estuary proximal to long established sources of catchment pollution.

  13. Northern New Mexico regional airport market feasibility

    SciTech Connect

    Drake, R.H.; Williams, D.S.

    1998-06-01

    This report is about the market for airline travel in northern New Mexico. Interest in developing a northern New Mexico regional airport has periodically surfaced for a number of years. The New Mexico State Legislature passed a memorial during the 1998 Second Session calling for the conduct of a study to determine the feasibility of building a new regional airport in NNM. This report is a study of the passenger market feasibility of such an airport. In addition to commercial passenger market feasibility, there are other feasibility issues dealing with siting, environmental impact, noise, economic impact, intermodal transportation integration, region-wide transportation services, airport engineering requirements, and others. These other feasibility issues are not analyzed in any depth in this report although none were discovered to be show-stoppers as a by-product of the authors doing research on the passenger market itself. Preceding the need for a detailed study of these other issues is the determination of the basic market need for an airport with regular commercial airline service in the first place. This report is restricted to an in-depth look at the market for commercial passenger air service in NNM. 20 figs., 8 tabs.

  14. Ceramic automotive Stirling engine program

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The Ceramic Automotive Stirling Engine Program evaluated the application of advanced ceramic materials to an automotive Stirling engine. The objective of the program was to evaluate the technical feasibility of utilizing advanced ceramics to increase peak engine operating temperature, and to evaluate the performance benefits of such an increase. Manufacturing cost estimates were also developed for various ceramic engine components and compared with conventional metallic engine component costs.

  15. Ceramic Automotive Stirling Engine Program

    SciTech Connect

    Not Available

    1986-08-01

    The Ceramic Automotive Stirling Engine Program evaluated the application of advanced ceramic materials to an automotive Stirling engine. The objective of the program was to evaluate the technical feasibility of utilizing advanced ceramics to increase peak engine operating temperature, and to evaluate the performance benefits of such an increase. Manufacturing cost estimates were also developed for various ceramic engine components and compared with conventional metallic engine component costs.

  16. Sediment Transport Processes In River Dominated Sub-Tropical Estuaries

    NASA Astrophysics Data System (ADS)

    DAquino, Carla; Schettini, Carlos

    2014-05-01

    The objective of this study is to present a comparative assessment of the largest three river dominated estuaries in the southern coast of the state of Santa Catarina, Brazil (Tubaro, Ararangu and Mampituba estuaries). The study was focused on mechanisms of transport of suspended sediments influenced by its morphologic and hydrodynamics characteristics. As shown in D'Aquino et al (2011), these estuaries share common attributes (climate and tides) and follow the basic conceptual model of fine sediment transport (presented by Toldo & Schettini (2006). However, each one has its own particularities regarding the geographical setting, land use, hypsometry, outfall, etc. The methodology used to the field measurements was the same for all estuaries, aiming at measuring the currents, water level, salinity, temperature and turbidity near the outfall for at least two complete tidal cycles (~25 hours). All the campaigns were carried on under syzygya tide conditions. During the sample collecting period, a longitudinal profile was conducted in each estuary, through acquisitions of salinity and temperature of the water column in every kilometer. In the Tubaro and Ararangu rivers estuaries, the concentration of suspended particulate matter (SPM) is mostly influenced by the periods of incoming tide, flood currents. In the Mampituba river estuary, the flocculation process was observed during the encounter of fresh and salt water in every tide entrance. It was possible to observe that the Ararangu river estuary, in what concerns the bottom SPM, responds to the variation of salinity and currents along the bottom. The Tubaro estuary presents a relation between the salinity and the bottom currents. In the Mampituba estuary no relevant correlation was found between the SPM, the salinity, and the bottom currents. Those aspects demonstrate that even sharing some characteristics there are significant differences among these estuaries. In addition, as a result of the comparative study, an analytical model was proposed that correlates the fluvial discharge, salt wedge, and SPM. This model might represent a tool to encourage discussions and help the scientific exploration of the estuaries in the south of Santa Catarina.

  17. Simultaneous atmospheric correction and quantification of suspended particulate matter in the Guadalquivir estuary from Landsat images

    NASA Astrophysics Data System (ADS)

    Carpintero, M.; Polo, M. J.; Suhyp Salama, Mhd.

    2015-05-01

    Earth observations (EOs) following empirical and/or analytical approaches are a feasible alternative to obtain spatial and temporal distribution of water quality variables. The limitations observed in the use of empirical approaches to estimate high concentrations of suspended particulate matter (SPM) in the estuarine water of Guadalquivir have led the authors to use a semi-analytical model, which relates the water constituents' concentration to the water leaving reflectance. In this work, the atmospheric correction has been carried out simultaneously and the aerosol reflectance and backscattering coefficients of SPM obtained. The results are validated using in situ SPM data series provided by a monitoring network in the study area. The results show that the model allows us to successfully estimate backscattering coefficients of SPM in the estuary, differentiating clear and turbid water and using two ?(4,5) .These considerations improve the value of R2 from 0.68 (single ?(4,5)) to 0.86 (two ?( 4,5)) on 18 May 2009. This method could be used as a preliminary approach to obtain SPM concentration in the Guadalquivir estuary with the limitations that the model shows for turbid waters.

  18. Seasonal Patterns in the Fish and Crustacean Community of a Turbid Temperate Estuary (Zeeschelde Estuary, Belgium)

    NASA Astrophysics Data System (ADS)

    Maes, J.; Taillieu, A.; Van Damme, P. A.; Cottenie, K.; Ollevier, F.

    1998-08-01

    Fish and crustaceans were sampled for 1 year in the upper reaches of a temperate estuary characterized by high turbidity and a tidal range of up to 5 m. Samples were taken in the cooling-water circuit of the Doel Nuclear Power station (Zeeschelde, Belgium). Between July 1994 and June 1995, 55 fish species, two shrimp species and four crab species were recorded. The fish community was composed of 36 marine species, 16 freshwater species and three diadromous species. Shrimps, Gobiidae and Clupeidae dominated the samples both in numbers and biomass. An exceptionally clear seasonal succession was observed in the species composition. It is argued that young fish and crustaceans use the highly turbid Zeeschelde Estuary as a refuge from predators.

  19. Multi-Scale Action Effectiveness Research in the Lower Columbia River and Estuary, 2011 - FINAL ANNUAL REPORT

    SciTech Connect

    Sather, Nichole K.; Storch, Adam; Johnson, Gary E.; Teel, D. J.; Skalski, J. R.; Bryson, Amanda J.; Kaufmann, Ronald M.; Woodruff, Dana L.; Blaine, Jennifer; Kuligowski, D. R.; Kropp, Roy K.; Dawley, Earl M.

    2012-05-31

    The study reported here was conducted by researchers at Pacific Northwest National Laboratory (PNNL), the Oregon Department of Fish and Wildlife (ODFW), the University of Washington (UW), and the National Marine Fisheries Service (NMFS) for the U.S. Army Corps of Engineers, Portland District (USACE). This research project was initiated in 2007 by the Bonneville Power Administration to investigate critical uncertainties regarding juvenile salmon ecology in shallow tidal freshwater habitats of the lower Columbia River. However, as part of the Washington Memorandum of Agreement, the project was transferred to the USACE in 2010. In transferring from BPA to the USACE, the focus of the tidal freshwater research project shifted from fundamental ecology toward the effectiveness of restoration in the Lower Columbia River and estuary (LCRE). The research is conducted within the Action Agencies Columbia Estuary Ecosystem Restoration Program (CEERP). Data reported herein spans the time period May 2010 to September 2011.

  20. Causes and effects of a highly successful marine invasion: Case-study of the introduced Pacific oyster Crassostrea gigas in continental NW European estuaries

    NASA Astrophysics Data System (ADS)

    Troost, Karin

    2010-10-01

    Since the 1960's, the Pacific oyster Crassostrea gigas has been introduced for mariculture at several locations within NW Europe. The oyster established itself everywhere and expanded rapidly throughout the receiving ecosystems, forming extensive and dense reef structures. It became clear that the Pacific oyster induced major changes in NW European estuaries. This paper reviews the causes of the Pacific oyster's remarkably successful establishment and spread in The Netherlands and neighbouring countries, and includes a comprehensive review of consequences for the receiving communities. Ecosystem engineering by C. gigas and a relative lack of natural enemies in receiving ecosystems are identified as the most important characteristics facilitating the invader's successful establishment and expansion. The Pacific oyster's large filtration capacity and eco-engineering characteristics induced many changes in receiving ecosystems. Different estuaries are affected differently; in the Dutch Oosterschelde estuary expanding stocks saturate the carrying capacity whereas in the Wadden Sea no such problems exist. In general, the Pacific oyster seems to fit well within continental NW European estuarine ecosystems and there is no evidence that the invader outcompetes native bivalves. C. gigas induces changes in plankton composition, habitat heterogeneity and biodiversity, carrying capacity, food webs and parasite life cycles. The case of the Pacific oyster in NW European estuaries is only one example in an increasing series of biological invasions mediated by human activities. This case-study will contribute to further elucidating general mechanisms in marine invasions; invasions that sometimes appear a threat, but can also contribute to ecological complexity.

  1. Design feasibility via ascent optimality for next-generation spacecraft

    NASA Astrophysics Data System (ADS)

    Miele, A.; Mancuso, S.

    This paper deals with the optimization of the ascent trajectories for single-stage-sub-orbit (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem is studied for different values of the engine specific impulse and spacecraft structural factor. The main conclusions are that: feasibility of SSSO spacecraft is guaranteed for all the parameter combinations considered; feasibility of SSTO spacecraft depends strongly on the parameter combination chosen; not only feasibility of TSTO spacecraft is guaranteed for all the parameter combinations considered, but the TSTO payload is several times the SSTO payload. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, aerodynamic improvements do not yield significant improvements in payload. For SSSO, SSTO, and TSTO spacecraft, simple engineering approximations are developed connecting the maximum payload weight to the engine specific impulse and spacecraft structural factor. With reference to the specific impulse/structural factor domain, these engineering approximations lead to the construction of zero-payload lines separating the feasibility region (positive payload) from the unfeasibility region (negative payload).

  2. Use of the USEPA Estuary Nitrogen Model to Estimate Concentrations of Total Nitrogen in Estuaries Using Loads Calculated by Watershed Models and Monitoring Data

    EPA Science Inventory

    We use USEPAs Estuary Nitrogen Model (ENM) to calculate annual average concentrations of total nitrogen (TN) in ten estuaries or sub-estuaries along the Atlantic coast from New Hampshire to Florida. These include a variety of systems, ranging from strongly-flushed bays to weakly...

  3. Use of the USEPA Estuary Nitrogen Model to Estimate Concentrations of Total Nitrogen in Estuaries Using Loads Calculated by Watershed Models and Monitoring Data

    EPA Science Inventory

    We use USEPA’s Estuary Nitrogen Model (ENM) to calculate annual average concentrations of total nitrogen (TN) in ten estuaries or sub-estuaries along the Atlantic coast from New Hampshire to Florida. These include a variety of systems, ranging from strongly-flushed bays to weakly...

  4. Vulnerability Assessments in Support of the Climate Ready Estuaries Program: A Novel Approach Using Expert Judgment, Volume I: Results for the San Francisco Estuary Partnership (Final Report)

    EPA Science Inventory

    Cover of the San Francisco <span class=Estuary Partnership Climate Ready Estuaries Program Final Report"> As part of the Climate Ready Estuaries (CRE) pr...

  5. Vulnerability Assessments in Support of the Climate Ready Estuaries Program: A Novel Approach Using Expert Judgment, Volume I: Results for the San Francisco Estuary Partnership (Final Report)

    EPA Science Inventory

    Cover of the San Francisco <span class=Estuary Partnership Climate Ready Estuaries Program Final Report"> As part of the Climate Ready Estuaries (CRE) pr...

  6. MODIS water quality algorithms for northwest Florida estuaries

    EPA Science Inventory

    Synoptic and frequent monitoring of water quality parameters from satellite is useful for determining the health of aquatic ecosystems and development of effective management strategies. Northwest Florida estuaries are classified as optically-complex, or waters influenced by chlo...

  7. The ecology of Tijuana Estuary, California: An estuarine profile

    SciTech Connect

    Zedler, J.B.; Nordby, C.S.

    1986-06-01

    This is the first attempt to synthesize and interpret a rapidly growing data base on the estuary's diverse biota - its vegetation, algae, birds, fishes, and invertebrates. Because so many changes have occurred in response to recent catastrophic events, we describe how each aspect of the estuary appeared before 1980 and how it has responded to several perturbations. The experimental tests of these cause-effect relationships have not been completed, and there is little reason to expect that environmental conditions have stabilized or that new types of disturbances won't occur. Thus, this profile should be viewed as a stage in the process of understanding Tijuana Estuary. Like the estuary itself, our knowledge is continuously evolving.

  8. NEKTON-HABITAT ASSOCIATIONS IN A PACIFIC NORTHWEST (USA) ESTUARY

    EPA Science Inventory

    Nekton?habitat associations were determined in Yaquina Bay, Oregon, United States, using a stratified-by-habitat, random, estuary-wide sampling design. Three habitats (intertidal eelgrass [Zostera marina], mud shrimp [Upogebia pugettensis], and ghost shrimp [Neotrypaea californie...

  9. HIGH CYANOBACTERIAL ABUNDANCE IN GULF OF MEXICO ESTUARIES

    EPA Science Inventory

    Aquatic phytoplankton comprise a wide variety of taxa spanning more than 2 orders of magnitude in size, yet studies of estuarine phytoplankton often overlook the picoplankton, particularly chroococcoid cyanobacteria (c.f. Synechocococcus). Three Gulf of Mexico estuaries (Apalachi...

  10. BACTERIOPLANKTON DYNAMICS IN A SUBTROPICAL ESTUARY: EVIDENCE FOR SUBSTRATE LIMITATION

    EPA Science Inventory

    Bacterioplankton abundance and metabolic characteristics were measured along a transect in Pensacola Bay, Florida, USA, to examine the factors that control microbial water column processes in this subtropical estuary. The microbial measures included 3 H-L-leucine incorporation, e...

  11. MAPPING BURROWING SHRIMP AND SEAGRASS IN YAQUINA ESTUARY

    EPA Science Inventory

    Burrowing shrimp and seagrasses create extensive intertidal and shallow subtidal habitats within Pacific NW estuaries. Maps of their populations are useful to inform estuarine managers of locations that deserve special consideration for conservation, and to inform oyster farmers...

  12. Effects of Catchment Activities on Macrofaunal Assemblages in Tasmanian Estuaries

    NASA Astrophysics Data System (ADS)

    Edgar, G. J.; Barrett, N. S.

    2000-05-01

    Silt loadings associated with human activities in catchments were inferred to have an extremely widespread effect on estuarine macrobenthos around Tasmania. Estuaries with human population densities exceeding 10 km-2in catchments consistently possessed muddy rather than sandy beds and shores, and were dominated by infauna rather than epifauna. Estuaries with human population densities below 1 km-2in catchments possessed sandy sediments and numerous epifaunal species. These effects were consistent within groups of estuaries possessing similar hydrology and geomorphology. Although faunal composition differed substantially between estuaries possessing low and high human population densities, the number of macrofaunal species was similar. Population effects therefore could neither be detected using species richness indices, nor by the ABC method. Faunal changes were most clearly detected using disturbance indices weighted by the sensitivity of individual species to human activity. Two such indices, which are based on abundance (DIn) and productivity (DIp) data, are suggested to provide useful local indicators of estuarine health.

  13. FRESHWATER INFLOWS: WATER FOR HEALTHY ESTUARIES CONFERENCE (MX96476507

    EPA Science Inventory

    The grantee will hold an interstate workshop on Freshwater Inflow issues in the Gulf of Mexico coastal region. The conference will identify water management questions to be addressed regarding providing freshwater inflows to estuaries, update participants on the current scientif...

  14. OXYGEN UPTAKE AND NUTRIENT REGENERATION IN THE PECONIC ESTUARY

    EPA Science Inventory

    EXECUTIVE SUMMARY: OXYGEN UPTAKE AND NUTRIENT REGENERATION IN THE PECONIC ESTUARY Rates of oxygen consumption and nutrient regeneration were measured annually throughout the Peconic Estuarine System. Sediment and water column oxygen uptake were measured to determine the potential...

  15. Landscape Thresholds and the Condition of Northeastern Estuaries

    EPA Science Inventory

    Anthropogenic impacts to northeastern estuaries have been well documented and many researchers have quantified the associations between broad scale human land uses in contributing landscapes and impacted estuarine condition. However, associations alone are not adequate for ident...

  16. LOUISIANIAN PROVINCE DEMONSTRATION REPORT - EMAP-ESTUARIES: 1991

    EPA Science Inventory

    This report summarizes the Louisianian Demonstration Project conducted by the Estuaries Resource Group of the Environmental Monitoring and Assessment Program (EMAP), a national program initiated by EPA to integrate efforts of governmental agencies in evaluations of status and tre...

  17. Evaluating Causes of Ecological Impairments in the Estuaries of Ukraine

    EPA Science Inventory

    Ukrainian estuaries have not undergone a systematic evaluation of the causes of ecological impairments caused by anthropogenic contamination. The objective of this evaluation is to use recently developed diagnostic tools to determine the causes of benthic ecological impairments. ...

  18. NEKTON-HABITAT ASSOCIATIONS IN A PACIFIC NORTHWEST (USA) ESTUARY

    EPA Science Inventory

    Nekton−habitat associations were determined in Yaquina Bay, Oregon, United States, using a stratified-by-habitat, random, estuary-wide sampling design. Three habitats (intertidal eelgrass [Zostera marina], mud shrimp [Upogebia pugettensis], and ghost shrimp [Neotrypaea californie...

  19. BARNEGAT BAY ESTUARY PROGRAM - OCEAN COUNTY BUILD-OUT ANALYSIS

    EPA Science Inventory

    Rutgers University, under contract with NJDEP, using funds available through Section 320 of the Clean Water Act (National Estuary Program), has completed an analysis of possible future conditions of the Barnegat Bay watershed using existing zoning ordinances throughout Ocean Coun...

  20. Annual cycle of hypoxia off the Changjiang (Yangtze River) Estuary.

    PubMed

    Wang, Baodong; Wei, Qinsheng; Chen, Jianfang; Xie, Linping

    2012-06-01

    The annual cycle of hypoxia off the Changjiang Estuary, China, was assessed from data acquired during nine cruises in 2006-2007. Hypoxia began to develop in late spring and early summer, reached its maximum in August, weakened in the autumn and finally disappeared in the winter. Hypoxia first developed south-east of the Changjiang Estuary in June, appeared in the east and north-east in July, and spread both south and north of the Changjiang Estuary in August. By September, it had started to recede in the north-east, and had dissipated in the southern part of the studied area by winter. The geographical displacement of the hypoxic zone was controlled by both seasonal changes in regional water column stratification and variations of the northward extension of the Taiwan Warm Current toward the Changjiang Estuary. PMID:22240466

  1. Cohesive Sediment Transport in the Jiaojiang River Estuary, China

    NASA Astrophysics Data System (ADS)

    Guan, W. B.; Wolanski, E.; Dong, L. X.

    1998-06-01

    Extensive data were obtained of the water and fine sediment dynamics during spring tides in the extremely turbid Jiaojiang River estuary at spring tides. These data enabled the calibration of a two-dimensional (2-D) width-integrated model. Four processes dominated the mud dynamics. These were, firstly, the formation at slack tide of soft mud deposits with an erosion constant much smaller than that of the underlying compacted sediment, secondly the sediment-induced buoyancy effects, thirdly the collapse of the turbulence by the sediment suspension in the fluid mud range and fourthly the inflow of sediment at the mouth of the estuary. These findings demonstrate the necessity to have detailed field data to enable quantitative, as opposed to qualitative, modelling of mud dynamics in turbid estuaries. The estuary is infilling with sediment from the East China Sea and not from riverine inflow, this sediment presumably originates from the Yangtze River located 200 km further north.

  2. CASCO BAY ESTUARY PROJECT TRIENNIAL IMPLEMENTATION REVIEW MARCH, 2004

    EPA Science Inventory

    The Casco Bay Estuary Project has seven primary goals/priorities which include: minimize pollutant loading from stormwater; open and protect shellfish beds; protect and restore habitat; reduce toxic pollution; promote responsible stewardship; sustain and promote the continued eff...

  3. DOWNSTREAM MIGRATION OF SALMONID SMOLTS IN OREGON RIVERS AND ESTUARIES

    EPA Science Inventory

    Migratory fish passage is an important designated use for many Oregon estuaries. Acoustic transmitters were implanted in coho smolts in 2004 and 2006 to evaluate how estuarine habitat, and habitat loss, might affect population health. Acoustic receivers that identified individu...

  4. SPATIAL DISTRIBUTIONS OF BURROWING SHRIMP POPULATIONS IN TWO OREGON ESTUARIES

    EPA Science Inventory

    Thalassinid burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) inhabit large expanses of Pacific estuarine tide flats, from British Columbia to Baja California. The spatial distribution of shrimp populations within estuaries has rarely been quantified because ...

  5. Hydrology of major estuaries and sounds of North Carolina

    USGS Publications Warehouse

    Giese, G.L.; Wilder, Hugh B.; Parker, Garald G., Jr.

    1979-01-01

    Knowledge of the basic hydrology of North Carolina 's major estuaries and sounds is necessary to help solve hydrology-related estuarine problems which include contamination of some estuaries with municipal and industrial wastes and drainage from adjacent intensively-farmed areas, nuisance-level algal blooms, excessive shoaling in some navigation channels, saltwater intrusion into usually fresh estuarine reaches, too-high or too-low salinities in nursery areas for various estuarine species, and flood damages due to hurricanes. Saltwater intrusion occurs from time to time in all major estuaries in North Carolina except the Roanoke River, where releases from Roanoke Rapids Lake and other reservoirs during otherwise low-flow periods effectively block saline water from the estuary. (Woodard-USGS)

  6. Environmental forcing on jellyfish communities in a small temperate estuary.

    PubMed

    Primo, Ana Lgia; Marques, Snia C; Falco, Joana; Crespo, Daniel; Pardal, Miguel A; Azeiteiro, Ulisses M

    2012-08-01

    The impact of biological, hydrodynamic and large scale climatic variables on the jellyfish community of Mondego estuary was evaluated from 2003 to 2010. Plankton samples were collected at the downstream part of the estuary. Siphonophora Muggiaea atlantica and Diphyes spp. were the main jellyfish species. Jellyfish density was generally higher in summer and since 2005 densities had increased. Summer community analysis pointed out Acartia clausi, estuarine temperature and salinity as the main driven forces for the assemblage's structure. Also, Chl a, estuarine salinity, runoff and SST were identified as the major environmental factors influencing the siphonophores summer interannual variability. Temperature influenced directly and indirectly the community and fluctuation of jellyfish blooms in the Mondego estuary. This study represents a contribution to a better knowledge of the gelatinous plankton communities in small temperate estuaries. PMID:22770533

  7. SAN JUAN BAY ESTUARY PROGRAM IMPLEMENTATION REVIEW ATTACHMENTS

    EPA Science Inventory

    A compilation of attachments referenced in the San Juan Bay Estuary Program Implementation Review (2004). Materials include, entity reports, water and sediment quality action plans, progress reports, correspondence with local municipalities and Puerto Rican governmental agencies,...

  8. A PROBABILISTIC SURVEY OF SEDIMENT TOXICITY IN WEST COAST ESTUARIES

    EPA Science Inventory

    A probabalistic survey of coastal condition assessment was conducted in 1999 by participants in US EPA's Environmental Monitoring and Assessment Program (EMAP). The survey targeted estuaries along the outer coasts of Washington, Oregon and California, including the lower Columbi...

  9. Turbidity and sediment transport in a muddy sub-estuary

    NASA Astrophysics Data System (ADS)

    Uncles, R. J.; Stephens, J. A.

    2010-04-01

    Sub-estuaries, i.e. tidal creeks and also larger estuaries that branch off the stem of their main estuary, are commonplace in many estuarine systems. Their physical behaviour is affected not only by tributary inflows, winds and tides, but also by the properties and behaviour of their main estuary. Measurements extending over more than an annual cycle are presented for the Tavy Estuary, a sub-estuary of the Tamar Estuary, UK. Generally, waves are small in the Tavy because of the short wind fetch. A several-hour period of up-estuary winds, blowing at speeds of between 7 and 10 m s -1, generates waves with significant wave heights of 0.25 m and a wave periodicity of 1.7 s that are capable of eroding the bed over the shallow, ca. 1.5 m-deep mudflats. Waves also influence sedimentation within and near salt marsh areas. An estuarine turbidity maximum (ETM) occurs in the Tavy's main channel, close to the limit of salt intrusion at HW. Suspended particulate matter (SPM) concentrations typically are less than 40 mg l -1 at HW, although concentrations can exceed 80 mg l -1 when tides and winds are strong. Flood-tide SPM inputs to the Tavy from the Tamar are greater during high runoff events in the River Tamar and also at spring tides, when the Tamar has a high-concentration ETM. Higher SPM concentrations are experienced on the mudflats following initial inundation. Without wave resuspension, this is followed by a rapid decrease in SPM for most of the tide, indicating that the mudflats are depositional at those times. SPM concentrations on the mudflats again increase sharply prior to uncovering. Peak ebb tidal speeds at 0.15 m above the mudflat bed can exceed 0.26 m s -1 at spring tides and 0.4 m s -1 following high runoff events, which are sufficient to cause resuspension. Time-series measurements of sediment bed levels show strong seasonal variability. Higher and lower freshwater flows are associated with estimated, monthly-mean sediment transport that is directed out of, or into, the upper sub-estuary, respectively. Seasonal sediment transfers between the estuary and its sub-estuary are discussed.

  10. Monitoring Rehabilitation in Temperate North American Estuaries

    SciTech Connect

    Rice, Casimir A.; Hood, W Gregory; Tear, Lucinda M.; Simenstad, Charles; Williams, Gregory D.; Johnson, L. L.; Feist, B. E.; Roni, P.

    2005-02-01

    In this chapter, we propose that monitoring rehabilitation in estuarine ecosystems by necessity requires quantifying relationships between dynamic estuarine processes and sensitive indicators of ecosystem function. While we do discuss temperate systems in general, emphasis is placed on anadromous salmon habitats in the Pacific Northwest because anadromous fishes are such a major focus of rehabilitation efforts, and present some of the greater challenges in linking function of one segment of their life history to conditions in a specific habitat. We begin with a basic overview of the ecological and socioeconomic significance of, as well as anthropogenic effects on, estuaries. Next, we briefly summarize the various kinds of estuarine rehabilitation historically practiced in temperate regions, and review estuarine rehabilitation monitoring design and methods, highlighting the unique challenges involved in monitoring estuarine systems. We then close with a summary and conclusions.

  11. Columbia Bay, Alaska: an 'upside down' estuary

    USGS Publications Warehouse

    Walters, R.A.; Josberger, E.G.; Driedger, C.L.

    1988-01-01

    Circulation and water properties within Columbia Bay, Alaska, are dominated by the effects of Columbia Glacier at the head of the Bay. The basin between the glacier terminus and the terminal moraine (sill depth of about 22 m) responds as an 'upside down' estuary with the subglacial discharge of freshwater entering at the bottom of the basin. The intense vertical mixing caused by the bouyant plume of freshwater creates a homogeneous water mass that exchanges with the far-field water through either a two- or a three-layer flow. In general, the glacier acts as a large heat sink and creates a water mass which is cooler than that in fjords without tidewater glaciers. The predicted retreat of Columbia Glacier would create a 40 km long fjord that has characteristics in common with other fjords in Prince William Sound. ?? 1988.

  12. The ecological condition of south Florida estuaries.

    PubMed

    Macauley, J M; Summers, J K; Engle, V D; Harwell, L C

    2002-05-01

    An assessment of the ecological condition of south Florida estuaries based on regional probabilistic monitoring was conducted during the summer of 1995. Samples and data were collected on water and sediment quality, benthos, and fish tissue contaminants. Elevated concentrations of metals and pesticides were measured in both sediments and fish tissue with some exceedances of guidance values. Bottom dissolved oxygen levels over 23-37% of the area were below state criteria. Eighty-eight percent of surface waters had greater than 10% penetration of ambient light to a depth of 1.0 m. Nine percent of the area studied in South Florida exhibited degraded biology and impaired use based on a calculated index of ecological condition. Using the probability-based monitoring design, useful information of this type can be provided to resource managers regarding estuarine condition on a regional scale. PMID:12004979

  13. Yeast community survey in the Tagus estuary.

    PubMed

    de Almeida, Joo M G C F

    2005-07-01

    The yeast community in the waters of the Tagus estuary, Portugal, was followed for over a year in order to assess its dynamics. Yeast occurrence and incidence were measured and this information was related to relevant environmental data. Yeast occurrence did not seem to depend upon tides, but river discharge had a dramatic impact both on the density and diversity of the community. The occurrence of some yeasts was partially correlated with faecal pollution indicators. Yeast isolates were characterized by microsatellite primed PCR (MSP-PCR) fingerprinting and rRNA gene sequencing. The principal species found were Candida catenulata, C. intermedia, C. parapsilosis, Clavispora lusitaniae, Debaryomyces hansenii, Pichia guilliermondii, Rhodotorula mucilaginosa and Rhodosporidium diobovatum. The incidence of these species was evaluated against the environmental context of the samples and the current knowledge about the substrates from which they are usually isolated. PMID:16329949

  14. Identification of Yeasts From the Suwannee River Florida Estuary1

    PubMed Central

    Lazarus, C. R.; Koburger, J. A.

    1974-01-01

    The yeast flora of the Suwannee River estuary in Florida has been studied. The predominant genera were Candida and Rhodotorula; however, the yeast most frequently isolated was Cryptococcus laurentii. Nine ascosporogenous species were isolated, with Hansenula saturnus predominating. The salinity range of the sediments was 0.4 to 20.6%; in the estuary water, 0.07 to 0.25%; and in the open Gulf of Mexico, 18 to 20%. Images PMID:16349995

  15. Biological effects of anthropogenic contaminants in the San Francisco Estuary

    USGS Publications Warehouse

    Thompson, B.; Adelsbach, T.; Brown, C.; Hunt, J.; Kuwabara, J.; Neale, J.; Ohlendorf, H.; Schwarzbach, S.; Spies, R.; Taberski, K.

    2007-01-01

    Concentrations of many anthropogenic contaminants in the San Francisco Estuary exist at levels that have been associated with biological effects elsewhere, so there is a potential for them to cause biological effects in the Estuary. The purpose of this paper is to summarize information about biological effects on the Estuary's plankton, benthos, fish, birds, and mammals, gathered since the early 1990s, focusing on key accomplishments. These studies have been conducted at all levels of biological organization (sub-cellular through communities), but have included only a small fraction of the organisms and contaminants of concern in the region. The studies summarized provide a body of evidence that some contaminants are causing biological impacts in some biological resources in the Estuary. However, no general patterns of effects were apparent in space and time, and no single contaminant was consistently related to effects among the biota considered. These conclusions reflect the difficulty in demonstrating biological effects due specifically to contamination because there is a wide range of sensitivity to contaminants among the Estuary's many organisms. Additionally, the spatial and temporal distribution of contamination in the Estuary is highly variable, and levels of contamination covary with other environmental factors, such as freshwater inflow or sediment-type. Federal and State regulatory agencies desire to develop biological criteria to protect the Estuary's biological resources. Future studies of biological effects in San Francisco Estuary should focus on the development of meaningful indicators of biological effects, and on key organism and contaminants of concern in long-term, multifaceted studies that include laboratory and field experiments to determine cause and effect to adequately inform management and regulatory decisions. ?? 2006 Elsevier Inc. All rights reserved.

  16. Juvenile Salmon Usage of the Skeena River Estuary

    PubMed Central

    Carr-Harris, Charmaine; Gottesfeld, Allen S.; Moore, Jonathan W.

    2015-01-01

    Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2–8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that use the estuary, then numerous fisheries would also be negatively affected. PMID:25749488

  17. Continuous resistivity profiling data from the Corsica River Estuary, Maryland

    USGS Publications Warehouse

    Cross, V.A.; Bratton, J.F.; Worley, C.R.; Crusius, J.; Kroeger, K.D.

    2011-01-01

    Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine its importance in nutrient delivery to the Chesapeake Bay. The Corsica River Estuary represents a coastal lowland setting typical of much of the eastern bay. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the lower estuary in April and May 2007. Resource managers are concerned about nutrients that are entering the estuary via SGD that may be contributing to eutrophication, harmful algal blooms, and fish kills. Techniques employed in the study included continuous resistivity profiling (CRP), piezometer sampling of submarine groundwater, and collection of a time series of radon tracer activity in surface water. A CRP system measures electrical resistivity of saturated subestuarine sediments to distinguish those bearing fresh water (high resistivity) from those with saline or brackish pore water (low resistivity). This report describes the collection and processing of CRP data and summarizes the results. Based on a grid of 67.6 kilometers of CRP data, low-salinity (high-resistivity) groundwater extended approximately 50-400 meters offshore from estuary shorelines at depths of 5 to >12 meters below the sediment surface, likely beneath a confining unit. A band of low-resistivity sediment detected along the axis of the estuary indicated the presence of a filled paleochannel containing brackish groundwater. The meandering paleochannel likely incised through the confining unit during periods of lower sea level, allowing the low-salinity groundwater plumes originating from land to mix with brackish subestuarine groundwater along the channel margins and to discharge. A better understanding of the spatial variability and geological controls of submarine groundwater flow beneath the Corsica River Estuary could lead to improved models and mitigation strategies for nutrient over-enrichment in the estuary and in other similar settings.

  18. Juvenile salmon usage of the Skeena River estuary.

    PubMed

    Carr-Harris, Charmaine; Gottesfeld, Allen S; Moore, Jonathan W

    2015-01-01

    Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2-8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that use the estuary, then numerous fisheries would also be negatively affected. PMID:25749488

  19. Two-dimensional hydrodynamic model of St. Lucie Estuary

    SciTech Connect

    Hu, G.G.

    1999-07-01

    A two-dimensional hydrodynamic model of St. Lucie Estuary was developed to assess the impact of drainage canal discharge and storm water runoff. Water surface elevation, two-dimensional velocity field and salinity are collected during 1998--1998 ENSO episode. The data sets cover an eight months period that includes both wet ad dry weather conditions. The model has been applied to St. Lucie Estuary salinity study. It will also provide flow fields to a water quality model.

  20. Intertidal morphology change following Spartina anglica introduction, Tamar Estuary, Tasmania

    NASA Astrophysics Data System (ADS)

    Sheehan, Matthew R.; Ellison, Joanna C.

    2014-08-01

    The surface morphology and sediment characteristics of introduced Spartina anglica marshes of the Tamar Estuary were analysed using a combination of spatial mapping, land-based topographical surveys, sediment coring and identification of the pre-introduction surface. Such a morphological investigation of estuarine change following Spartina introduction has not been attempted elsewhere before. A difference was found between marshes in upper and lower estuary. Surface topography of Type-1 marshes of the upper estuary was found to be independent of the pre-Spartina surface morphology, with deeper vertical development and exhibiting a flat to slightly concave upper marsh, a convex ridge in the outer mid marsh, and a relatively steeply graded convex lower marsh. Type-2 marshes of the lower estuary were thinner in vertical development, and with surface topography dictated by the underlying pre-Spartina surface. The difference was found to be due to variations in environmental conditions in sediment supply and wave/current exposure between the two regions rather being an indication of relative maturity. The seaward edge of marshes was found to be 0.5 m lower at the seaward end of the Tamar relative to the landward, reflecting tidal amplification up this confined estuary. While Spartina marshes are accretionary, surveys demonstrated retreat of the seaward margins throughout the estuary over the past 17 years, and the development of erosional scarps in Type-1 marshes. Spatial mapping identified 374 ha of S. anglica infestation within the Tamar Estuary, with Type-1 marshes occupying 240 ha and Type-2 marshes occupying 134 ha. Topographic profiles and stratigraphic data were used to estimate total sediment volumes trapped by Spartina in the Tamar Estuary, finding approximately 1,193,441 m3 of material to have been trapped beneath Spartina since its introduction in 1947, of which between 14 and 28% has been Spartina-derived organic matter.

  1. Remote sensing of tidal chlorophyll-a variations in estuaries

    USGS Publications Warehouse

    Catts, Glenn P.; Khorram, Siamak; Cloern, James E.; Knight, Allen W.; Degloria, Stephen D.

    1985-01-01

    Knowledge of the distribution of phytoplankton and the location of this zone of high biomass is valuable in establishing management policies for this ecologically important estuary. Furthermore, the techniques used here may provide an alternative cost-effective method for assessing water-quality conditions and they may prove useful for studying spatial variations (patchiness) and seasonal variations in phytoplankton biomass in other estuaries and coastal waters.

  2. Nutrients, hypoxia and Mass Fishkill events in Tapi Estuary, India

    NASA Astrophysics Data System (ADS)

    Ram, Anirudh; Jaiswar, Jiyalal Ram M.; Rokade, M. A.; Bharti, S.; Vishwasrao, C.; Majithiya, D.

    2014-07-01

    From 1983 to 2011, dissolved oxygen (DO) conditions in the Tapi Estuary changed from normoxic to hypoxic due to increased and untreated discharge of sewage. Both tidal and day-night variations of DO were best explained by hydrographic factors, sewage pollution and phytoplankton dynamics in upper, middle, lower estuary and the coastal water. Hypoxia/anoxia was associated with low-flow periods due to riverine restrictions and changing in climatic condition. The upper Tapi Estuary becomes anoxic during summer irrespective of tide while the middle estuary was anoxic (<0.2 mg O2 l-1) during post and premonsoon seasons and hypoxic (<2.0 mg O2 l-1) during monsoon season. Differences in the degree of stratification, sewage discharge and flushing accounted for differences in DO. Because of high nutrient concentrations (maximum NO3--N 103.1, NO2--N 26.0, NH4+-N 104.0 and PO43--P 99.0 μmol l-1), the lower estuary remains DO deficient between 2.0 and 5.0 mg O2 l-1, most of the time. The environmental condition of Tapi Estuary has impacted the coastal water of the Arabian Sea in recent years with fish kills attributed to its hypoxic/anoxic condition. Enhanced concentrations of nutrients and organic matter from indiscriminate discharge of sewage into the Tapi Estuary and restricted flushing as a result of construction of a series of dams in the catchment area of the estuary are the primary factors that have lead to the development of hypoxia.

  3. Reprint of Water renewal timescales in the Scheldt Estuary

    NASA Astrophysics Data System (ADS)

    de Brye, Benjamin; de Brauwere, Anouk; Gourgue, Olivier; Delhez, Eric J. M.; Deleersnijder, Eric

    2013-12-01

    Using the concepts of the Constituent-oriented Age and Residence time Theory (CART), we compute timescales related to the water renewal in the Scheldt Estuary (The Netherlands/Belgium). Three different timescales are used to better understand and characterize the dynamics of the estuary: the age of the renewing water, the residence time and the exposure time. The residence time is the time taken by a water parcel to leave the estuary for the first time while the exposure time is the total time spent by a water parcel in the estuary including re-entries. The age of a renewing water parcel is defined as the time elapsed since it entered the estuary. The renewing water was split into three types: the water originating from the sea, the water originating from the upstream fresh tidal rivers and the water originating from the different canals and docks connected to the estuary. Every timescale is computed at any time and position by means of the finite-element, unstructured-mesh model SLIM. This results in movies of the timescale fields (shown as Supplementary material), allowing a detailed analysis of their spatial and temporal variabilities. The effect of the M2 tide and the discharge regime (winter, summer or average situation) on the timescales is also investigated.Tidally-averaged timescales vary little over the width of the estuary and hence exhibit a virtually one-dimensional behaviour. However, around these average values, the timescales can vary hugely over a tidal cycle, with amplitudes that significantly depend on the space coordinates. The reason thereof has yet to be elucidated. These results underscore the need for two- or three-dimensional models with high temporal resolution for investigating the dynamics of the Scheldt Estuary.

  4. Contamination and restoration of an estuary affected by phosphogypsum releases.

    PubMed

    Villa, M; Mosqueda, F; Hurtado, S; Mantero, J; Manjn, G; Periaez, R; Vaca, F; Garca-Tenorio, R

    2009-12-15

    The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides 226Ra and 210Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of 210Pb and 226Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for 226Ra and 210Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary can be performed via natural processes. PMID:19822348

  5. Modeling flocculation in a hypertidal estuary

    NASA Astrophysics Data System (ADS)

    Ramrez-Mendoza, Rafael; Souza, Alejandro J.; Amoudry, Laurent O.

    2014-01-01

    When fine particles are involved, cohesive properties of sediment can result in flocculation and significantly complicate sediment process studies. We combine data from field observations and state-of-the-art modeling to investigate and predict flocculation processes within a hypertidal estuary. The study site is the Welsh Channel located at the entrance of the Dee Estuary in Liverpool Bay. Field data consist of measurements from a fixed site deployment during 12-22 February 2008. Grain size, suspended sediment volume concentration, and current velocity were obtained hourly from moored instruments at 1.5 m above bed. Near-bottom water samples taken every hour from a research vessel are used to convert volume concentrations to mass concentrations for the moored measurements. We use the hydrodynamic model Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS) coupled with the turbulence model General Ocean Turbulence Model (GOTM) and a sediment module to obtain three-dimensional distributions of suspended particulate matter (SPM). Flocculation is identified by changes in grain size. Small flocs were found during flood and ebb periodsand correlate with strong currentsdue to breakup, while coarse flocs were present during slack waters because of aggregation. A fractal number of 2.4 is found for the study site. Turbulent stresses and particle settling velocities are estimated and are found to be related via an exponential function. The result is a simple semiempirical formulation for the fall velocity of the particles solely depending on turbulent stresses. The formula is implemented in the full three-dimensional model to represent changes in particle size due to flocculation processes. Predictions from the model are in agreement with observations for both settling velocity and SPM. The SPM fortnight variability was reproduced by the model and the concentration peaks are almost in phase with those from field data.

  6. Sources, Ages, and Alteration of Organic Matter in Estuaries.

    PubMed

    Canuel, Elizabeth A; Hardison, Amber K

    2016-01-01

    Understanding the processes influencing the sources and fate of organic matter (OM) in estuaries is important for quantifying the contributions of carbon from land and rivers to the global carbon budget of the coastal ocean. Estuaries are sites of high OM production and processing, and understanding biogeochemical processes within these regions is key to quantifying organic carbon (Corg) budgets at the land-ocean margin. These regions provide vital ecological services, including nutrient filtration and protection from floods and storm surge, and provide habitat and nursery areas for numerous commercially important species. Human activities have modified estuarine systems over time, resulting in changes in the production, respiration, burial, and export of Corg. Corg in estuaries is derived from aquatic, terrigenous, and anthropogenic sources, with each source exhibiting a spectrum of ages and lability. The complex source and age characteristics of Corg in estuaries complicate our ability to trace OM along the river-estuary-coastal ocean continuum. This review focuses on the application of organic biomarkers and compound-specific isotope analyses to estuarine environments and on how these tools have enhanced our ability to discern natural sources of OM, trace their incorporation into food webs, and enhance understanding of the fate of Corg within estuaries and their adjacent waters. PMID:26407145

  7. PCBs in the fish assemblage of a southern European estuary

    NASA Astrophysics Data System (ADS)

    Baptista, Joana; Pato, Pedro; Pereira, Eduarda; Duarte, Armando C.; Pardal, Miguel A.

    2013-02-01

    The Mondego estuary fish assemblage was studied for the accumulation of PCBs. Three sampling stations were visited along an estuarine salinity gradient, and, in total, 15 species were collected. Analysis of PCBs revealed no significant differences among the sampling stations, although differences were observed among the fish assemblages. Fish assemblages could be divided into three groups. The first group comprised those with higher concentration (more than 10 ng g- 1, dw), included the species Gobius niger, Sardina pilchardus, Anguilla anguilla, Pomatoschistus microps, Chelidonichthys lucerna and Liza ramada; the second group with medium concentration (5-10 ng g- 1, dw), included the species Pomatoschistus minutus, Dicentrarchus labrax, Atherina presbyter, Chelon labrosus, Diplodus vulgaris, Platichthys flesus and Cilata mustela; and a third group with low concentration (less than 5 ng g- 1, dw), included the species Solea solea and Callionymus lyra. A positive correlation was found between lipid content and PCB concentrations. To evaluate the influence of the residence time of species on the accumulation of PCBs, species were divided into two groups: species that spend more than 3 years in the estuary, and species that spend less than 3 years in the estuary. Species that spend more than 3 years in the estuary presented higher concentrations than species that spend less than 3 years in the estuary. CBs 138 and 153 had higher concentration, and tended to increase with time spent in the estuary.

  8. PCB-resistant diatoms in the Hudson River estuary

    NASA Astrophysics Data System (ADS)

    Cosper, Elizabeth M.; Wurster, Charles F.; Bautista, Mark F.

    1988-02-01

    Diatom cells that are resistant, as well as sensitive, to the toxicity of polychlorinated biphenyls (PCB) are widespread throughout the highly polluted Hudson River estuary. A study of the distribution of PCB resistance among populations of the diatoms, Thalassiosira nordenskioldii and Asterionella glacialis, revealed few spatial or temporal patterns for the trait during spring and summer. The number of estuarine clones of A. glacialis tolerant of more than 25 ppb of PCB was greater than twice the number of clones isolated from nearshore waters at Sandy Hook, NJ. This suggests that selection pressure for PCB resistance is greater in the estuary than in the New York Bight apex. If specific sites of selection exist, the mixing of cells within the estuary may be rapid enough to distribute resistant clones throughout the estuary, or the selection process may involve a generalized response to a multitude of pollutants. Several clones of both species tested were not only tolerant of PCB, but were actually enhanced in their growth in the presence of PCB. Such clones were distributed throughout the estuary during both seasons. Selection in the estuary favours not only resistant strains of diatoms, but forms that may utilize organic pollutants.

  9. Causes of light attenuation in nine New Zealand estuaries

    NASA Astrophysics Data System (ADS)

    Vant, W. N.

    1990-08-01

    Optical properties and the constituent composition of the waters of nine northern New Zealand estuaries were determined during 1988-1989. Substantial variation was found both within and between the estuaries. For characteristics such as beam attenuation, turbidity and suspended solids, sources of variation in particular estuaries included: state of the tide (causing three-fold differences); seasonal changes (five to ten-fold); incomplete mixing, both horizontal (two to three-fold) and, in one case, vertical (about two-fold); and the presence of flood-waters (at least five-fold). The waters at the estuary mouths were fairly turbid (Secchi depths 12-44 m), and were comparatively bright (PAR reflectance 6-12%), because the constituents tended to scatter more light than they absorbed (7-17 times more on average). Phytoplankton biomass was low (chlorophyll ?, 05-5 mg m -3) and suspended particulates were mostly inorganic (82%). Equations were derived which described how the water constituents affected the estuaries' optical properties. Reasonably reliable predictions resulted when the equations were tested against a separate data set. The inorganic suspensoids (3-11 g m -3) caused 56% of beam attenuation, four times that caused by phytoplankton. Scattering per unit mass of suspensoids was several times lower than that found in some New Zealand lakes because of the larger average particle size of the estuarine material. Oxidation pond effluent discharged to one of the estuaries had little effect on beam attenuation there.

  10. Nonlinear interactions of waves and tides in a subterranean estuary

    NASA Astrophysics Data System (ADS)

    Xin, Pei; Wang, Shen S. J.; Lu, Chunhui; Robinson, Clare; Li, Ling

    2015-04-01

    Previous studies have revealed hysteretic behavior in subterranean estuaries in response to intensified wave conditions caused by offshore storm events, showing dependence of submarine groundwater discharge (SGD) and subsurface salt distribution on historic wave conditions. Although most shorelines worldwide are also exposed to tidal fluctuations, it is unclear how tides moderate wave-induced SGD and salinity distribution in subterranean estuaries. This study presents numerical simulations that explore the combined influence of intensified wave conditions and tides on groundwater flow and salt transport in a subterranean estuary. The results show that tides weaken the hysteretic wave effect on SGD, suggesting that a tidally influenced subterranean estuary is less sensitive to intensified wave conditions with respect to the water fluxes across the aquifer-sea interface. However, due to enhancement of salt-freshwater mixing, tides strengthen the hysteretic wave effect on the salt fluxes across the aquifer-sea interface, prolonging the recovery of salt distribution in the subterranean estuary to the prestorm state. These findings reveal the nonlinear, coupling nature of processes driven by oceanic oscillations at different time scales in subterranean estuaries.

  11. Fluxes and retention of trace metals in the Humber Estuary

    NASA Astrophysics Data System (ADS)

    Millward, G. E.; Glegg, G. A.

    1997-01-01

    The Humber Estuary is a physically dynamic system into which industrial wastes contaminated with heavy metals have been discharged for many years. The total fluxes of Cd, Cu, Fe, Ni, Pb and Zn from the Humber Estuary to the North Sea have been estimated for December 1988, May 1990 and August 1990. These fluxes have been compared to inputs into the estuary from rivers, sewage and industry as reported by the Paris Commission. A discrepancy exists between the estuarine inputs and the fluxes to the North Sea, which suggests that the estuary is acting as a trap for fine, metal-contaminated sediments. An alternative approach to flux assessment also indicates that metal retention by sediments is a major feature of the Humber Estuary. The results are discussed in the context of the recovery of the estuary from metal contamination and the consequences for the coastal zone. This critical review allows assessment of effectiveness of current management strategies and new directions for the future to be proposed.

  12. [The benthic fauna of Sabancuy Estuary, Campeche, Mexico].

    PubMed

    González Solís, A; Torruco Gómez, D

    2001-03-01

    The fish and invertebrates community structure in the Sabancuy estuary was analyzed in two seasons and 14 sampling stations (13 along the estuary and one in the marine adjacent coast). No significant differences were found between seasons. The environmental frame defines two zones within the estuary, the first extends from the access highway to Sabancuy town until the Pujo mouth in the west; the second from the bridge to the estuary head in the east. The most abundant invertebrates were mollusks (51.8% of the total), in biomass the crustaceans dominated. The fish included 21 families and 33 species; the most abundant were Gerridae, Scianidae, Sparidae, Lutjanidae and Ciprinodontidae. The highest diversities of both communities correspond to the central part of the estuary. These communities include three sections with notable differences in faunal distribution: one is influenced by the exit to Terminos lagoon, the secondary in the estuary head and a third is in a transition zone defined by the proximity of the town access bridge. The ecological organization suggests a strong division caused by the bridge, both sides are scarce in habitats and nutrient resources and this is reflected in the low species counts. PMID:11795160

  13. Feasibility studies of aquifer thermal energy storage

    SciTech Connect

    Hall, S. H.

    1993-01-01

    Determining the feasibility of using aquifer thermal energy storage (ATES) for a particular heating or cooling application is an interdisciplinary effort, requiring (at a minimum) expertise in engineering and hydrology. The feasibility study should proceed in two distinct stages. The first stage, which is limited in scope and detail, is intended to show if an ATES system is technically and economically suited to the application. Focus of this preliminary investigation is on revealing the existence of factors that might weigh heavily against the use of ATES methods, and, in the absence of such factors, on choosing a suitable scale for the ATES plant and well field. The results of the preliminary investigation are used to determine if more detailed investigation--including field studies--are justified, and to facilitate comparing the advantages of ATES to those of other means of providing heating or cooling. The second stage of the feasibility study focuses on detailed aquifer characterization, refinement of engineering design and cost estimates, and economic and environmental risk analysis. The results of this investigation, if favorable, will be used to justify the expense of constructing the ATES system.

  14. Columbia River Estuary data development program: tidal marsh plant production in the Columbia River Estuary. Final report

    SciTech Connect

    Macdonald, K.B.; Winfield, T.P.

    1984-06-01

    This report summarizes the final results of the Emergent Plant Primary Production Work Unit of the Columbia River Estuary Data Development Program (CREDDP). The report describes the species composition, standing crop, and production dynamics of the extensive areas of tidal marsh vegetation that fringe the shores of the Columbia River Estuary and form many of its islands. The role of marsh production is discussed within a conceptual framework of the entire estuarine ecosystem.

  15. A MEDLINE feasibility study.

    PubMed

    McGee, J L

    1980-07-01

    A MEDLINE feasibility study was conducted with the Northeastern Consortium for Health Information (NECHI) and sponsored by the New England Regional Medical Library Service. It is based on the theory that most potential users and supporters of MEDLINE within hospitals are unaware of its usefulness and applications, and that there exists a need for expanding MEDLINE services to more hospital libraries. The purpose of the study was to provide NECHI with an evaluation of MEDLINE as a feasible service by ascertaining the need and by evaluating the usefulness, satisfaction, and costs of the system. The study demonstrated sufficient use of MEDLINE to justify implementation within NECHI and it provided useful data to determine the future of MEDLINE in each institution. It documented that utilization improved rapidly with publicity and the presence of the system within an institution, that MEDLINE can be an effective and economical complement to the traditional reference services used to support information needs in hospitals, and that more hospital libraries should be able to implement MEDLINE to their advantage once potential users and supporters have been exposed to the system. PMID:6998531

  16. Numerical aerodynamic simulation facility feasibility study

    NASA Technical Reports Server (NTRS)

    1979-01-01

    There were three major issues examined in the feasibility study. First, the ability of the proposed system architecture to support the anticipated workload was evaluated. Second, the throughput of the computational engine (the flow model processor) was studied using real application programs. Third, the availability reliability, and maintainability of the system were modeled. The evaluations were based on the baseline systems. The results show that the implementation of the Numerical Aerodynamic Simulation Facility, in the form considered, would indeed be a feasible project with an acceptable level of risk. The technology required (both hardware and software) either already exists or, in the case of a few parts, is expected to be announced this year. Facets of the work described include the hardware configuration, software, user language, and fault tolerance.

  17. Tripropellant Engine Study

    NASA Technical Reports Server (NTRS)

    Wheeler, D. B.

    1977-01-01

    The feasibility of modifying the space shuttle main engine (SSME) for dual mode operation was investigated. Various high power cycle engine configurations derived from the SSME were configurations that will allow sequential burning of LOX/hydrocarbon and LOX/hydrogen were studied in order to identify concepts that make maximum use of SSME hardware and best satisfy the dual mode booster engine system application. Engine cycles were formulated for LOX/RP-1, LOX/CH4, and LOX/C3H8 propellants. Flow rates and operating cycles were established and the adaptability of the major components of the SSME was evaluated.

  18. Water Injection Feasibility for Boeing 747 Aircraft

    NASA Technical Reports Server (NTRS)

    Daggett, David L.

    2005-01-01

    Can water injection be offered at a reasonable cost to large airplane operators to reduce takeoff NO( sub x) emissions? This study suggests it may be possible. This report is a contract deliverable to NASA Glenn Research Center from the prime contractor, The Boeing Commercial Airplane Company of Seattle, WA. This study was supported by a separate contract to the Pratt & Whitney Engine Company of Hartford, CT (contract number NNC04QB58P). Aviation continues to grow and with it, environmental pressures are increasing for airports that service commercial airplanes. The feasibility and performance of an emissions-reducing technology, water injection, was studied for a large commercial airplane (e.g., Boeing 747 with PW4062 engine). The primary use of the water-injection system would be to lower NOx emissions while an important secondary benefit might be to improve engine turbine life. A tradeoff exists between engine fuel efficiency and NOx emissions. As engines improve fuel efficiency, by increasing the overall pressure ratio of the engine s compressor, the resulting increased gas temperature usually results in higher NOx emissions. Low-NO(sub x) combustors have been developed for new airplanes to control the increases in NO(sub x) emissions associated with higher efficiency, higher pressure ratio engines. However, achieving a significant reduction of NO(sub x) emissions at airports has been challenging. Using water injection during takeoff has the potential to cut engine NO(sub x) emissions some 80 percent. This may eliminate operating limitations for airplanes flying into airports with emission constraints. This study suggests an important finding of being able to offer large commercial airplane owners an emission-reduction technology that may also save on operating costs.

  19. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia).

    PubMed

    Musenze, Ronald S; Werner, Ursula; Grinham, Alistair; Udy, James; Yuan, Zhiguo

    2014-02-15

    Methane (CH4) and nitrous oxide (N2O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water-air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH4 and N2O all-year-round. Dissolved N2O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH4 concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH4 and N2O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N2O saturation significantly increased with NOx concentrations (r(2)=0.55). The estimated water-air fluxes varied between 0.1 and 3.4 mg N2O m(-2)d(-1) and 0.3 to 27.9 mg CH4 m(-2)d(-1). Total emissions (CO2-e) were N2O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. PMID:24333994

  20. Simulating tidal and storm surge hydraulics with a simple 2D inertia based model, in the Humber Estuary, U.K

    NASA Astrophysics Data System (ADS)

    Skinner, Christopher J.; Coulthard, Thomas J.; Parsons, Daniel R.; Ramirez, Jorge A.; Mullen, Liam; Manson, Susan

    2015-03-01

    The hydraulic modelling of tidal estuarine environments has been largely limited to complex 3D models that are computationally expensive. This makes them unsuitable for applications which make use of live data to make real/near time forecasts, such as the modelling of storm surge propagation and associated flood inundation risks. To address this requirement for a computationally efficient method a reduced complexity, depth-integrated 2D storage cell model (Lisflood-FP) has been applied to the Humber Estuary, UK. The capability of Lisflood-FP to reproduce the tidal heights of the Humber Estuary has been shown by comparing modelled and observed tidal stage heights over a period of a week. The feasibility of using the Lisflood-FP model to forecast flood inundation risk from a storm surge is demonstrated by reproducing the major storm surge that struck the UK East Coast and Humber Estuary on 5 December 2013. Results show that even for this 2013 extreme event the model is capable of reproducing the hydraulics and tidal levels of the estuary. Using present day flood defences and observed flooding extents, the modelled flood inundation areas produced by the model were compared, showing agreement in most areas and illustrating the model's potential as a now-casting early warning system when driven by publically available data, and in near real-time. The Lisflood-FP model used was incorporated into the CAESAR-Lisflood GUI, with the calibration and verification of the estuarine hydraulics reported herein being a key step in creating an estuary evolution model, capable of operating in the decadal to century timescales that are presently underrepresented in estuarine predictive capability, and ultimately developing a model to predict the evolution of flood risk over the longer term.

  1. Tidal asymmetry in estuaries with mixed semidiurnal/diurnal tides

    NASA Astrophysics Data System (ADS)

    Nidzieko, Nicholas J.

    2010-08-01

    Tidal asymmetry in estuaries with mixed, mainly semidiurnal tides arises from both the interaction of principal tides and the higher harmonics generated by distortions within the estuary. The duration asymmetry in rise and fall of water level caused by principal tides on the west coast of the continental United States is ebb-dominant, and so the tide entering estuaries is also ebb-dominant, prior to any internal distortions within the estuary. The interaction of higher harmonics with principal constituents either augments or cancels the duration asymmetry in the principal tides. In estuaries where tidal elevation and velocity phase are near quadrature (90 out of phase), the duration asymmetry in tidal elevation leads to asymmetries in tidal current magnitude. Asymmetry can be conveniently quantified in terms of the sample skewness, ?1, the normalized third sample moment about the mean. An analytic approximation to the skewness shows that traditional metrics of asymmetry, namely the ratio of constituent amplitudes and the relative constituent phase difference, arise from calculating the third sample moment. Observations from three California estuaries of different morphologies are presented as an illustration of how skewness can be used to quantify asymmetry in real systems. As in semidiurnal systems, morphology is a good predictor of whether higher harmonics engender ebb-dominance or flood-dominance, however asymmetry imposed by principal tides at the mouth must first be overcome and so there is a spatial evolution in the total asymmetry. Quantifying observations via skewness should be considered in addition to traditional metrics in estuaries with mixed tides.

  2. The status of fish conservation in South African estuaries.

    PubMed

    Whitfield, A K; Cowley, P D

    2010-06-01

    Estuary-dependent fish species are defined as those taxa whose populations would be adversely affected by the loss of estuarine habitats. Of the 155 species regularly recorded in South African estuaries, only 32 (21%) are completely dependent on these systems, but this figure increases to 103 species (66%) if partially dependent taxa are included in the analysis. The conservation of fishes in estuaries on the subcontinent is threatened by a number of factors, including habitat degradation, disruption of essential ecological processes, hydrological manipulations, environmental pollution, overexploitation due to fishing activities and, more recently, climate change and the effects of introduced aquatic animals. Although major threats to fishes are usually linked to environmental degradation, there is increasing evidence that the stocks of certain fish species are overexploited or collapsed. Fish conservation and fisheries management does not depend on the implementation of a single action, but rather the co-ordination of a detailed plan, often in a multidisciplinary context. Some examples of innovative means of contributing to estuarine fish conservation in a South African context include the determination and implementation of the ecological freshwater requirements for estuaries, the zoning of estuaries for different uses and the recognition that the maintenance of ecological processes are vital to aquatic ecosystem health. Apart from the designation of protected areas, the main direct means of conserving fish species and stocks include habitat conservation, controls over fishing methods, effort, efficiency and seasonality, pollution control and the prevention of artificial manipulation of estuary mouths. Since becoming a democracy in 1994, environmental legislation, policy and institutional arrangements in South Africa have undergone some major changes, which, if fully implemented, will be very positive for fish conservation in estuaries on the subcontinent. PMID:20557655

  3. Urban microbial ecology of a freshwater estuary of Lake Michigan

    PubMed Central

    Fisher, Jenny C.; Newton, Ryan J.; Dila, Deborah K.

    2015-01-01

    Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an “urban microbial signature,” and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas, and Pseudomonas, which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is likely to occur with potential long term impacts on the function of estuarine and nearshore ecosystems. PMID:26866046

  4. Generation of overtides and compound tides in Amazon estuary

    NASA Astrophysics Data System (ADS)

    Gallo, Marcos Nicols; Vinzon, Susana Beatriz

    2005-12-01

    Tidal propagation in estuaries is affected by friction and fresh water discharge, besides changes in the depth and morphology of the channel. Main distortions imply variations in the mean water level and asymmetry. Tidal asymmetry can be important as a mechanism for sediment accumulation and turbidity maximum formation in estuaries, while mean water level changes can affect navigation depths. Data from several gauges stations from the Amazon estuary and the adjacent coast were analyzed and a 2DH hydrodynamic model was configured in a domain covering the continental shelf up to the last section of the river where the tidal signature is observed. Based on data, theoretical and numerical results, the various influences in the generation of estuarine harmonics are presented, including that of fresh water discharge. It is shown that the main overtide, M4, derived from the most important astronomic component in the Amazon estuary, M2, is responsible for the tidal wave asymmetry. This harmonic has its maximum amplitude at the mouth, where minimum depths are found, and then decreases while tide propagates inside the estuary. Also, the numerical results show that the discharge does not affect water level asymmetry; however, the Amazon river discharge plays an important role in the behavior of the horizontal tide. The main compound tide in Amazon estuary, Msf, generated from the combination of the M2 and S2, can be strong enough to provoke neap low waters lower than spring ones. The results show this component increasing while going upstream in the estuary, reaching a maximum and then slightly decaying.

  5. Recovery simulations of grossly polluted sediments in the Bilbao Estuary.

    PubMed

    Antonio Gonzlez Oreja, Jos; Ignacio Saiz Salinas, Jos

    2003-01-01

    The Bilbao Estuary is one of the most contaminated estuaries on the north coast of Spain, and vast efforts have been made to abate pollution there. In fact, the local water authority has forecast a biological recovery of the native fauna after a substantial increase in dissolved oxygen to normoxic levels. In order to assess this prediction by evaluating the extent of natural regeneration of these polluted sediments, two long-term bioassays (t=90 d) were performed. In both of them, lethal (differences in survival) and sublethal (differences in length and weight growth) effects were measured by using juvenile individuals of the autochthonous clam, Scrobicularia plana (Da Costa, 1778). The sediments tested differed in pollution levels, as measured by a set of indicators including PAHs, PCBs, heavy metals, volatile organic matter and coprostanol. All sediments were finally exposed to normoxic conditions in situ in the Bilbao Estuary (DO approximately 6.3 mg l(-1)). In the first experiment, concerning moderately polluted sediments from the Bilbao Estuary and reference sediments from the "pristine" Plentzia Estuary, no significant differences (P>0.05) were found regarding animal survival (approximately 94.5%) or growth in length or weight between the sediments tested. In the second experiment, also involving grossly polluted sediments (GPS) from the Bilbao Estuary, survival (24.5%) was statistically lower (P<0.05) than in the other sediments (approximately 93%). No significant differences were found in growth (length, weight) between animals exposed to moderately polluted or reference sediments. We interpret this dramatic difference in survival as the lethal effect on the animals tested of the GPS of the Bilbao Estuary, indicating a situation where biological recovery is not possible due to the adverse consequences of contaminants sorbed into sediments. The extensive use of this inexpensive bioassay could help to distinguish sediments in which homeostatic recovery is possible from grossly polluted "hot spots", which need costly remedial actions. PMID:12535968

  6. Columbia River Estuary Ecosystem Classification Ecosystem Complex

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith Marcoe

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub-catena". The extent of detailed mapping is the interpreted Holocene geologic floodplain of the tidal Columbia River and its tributaries to the estimated head of tide. The extent of this dataset also includes tributary valleys that are not mapped in detail. The upstream extents of tributary valleys are an estimation of the limit of Columbia River influence and are for use as containers in future analyses. The geologic floodplain is the geomorphic surface that is actively accumulating sediment through occasional overbank deposition. Most features within the geologic floodplain are considered to be formed during the recent (Holocene-epoch) climatic regime. There are bedrock and pre-Holocene sedimentary deposits included where they are surrounded by Holocene sediment accumulations or have been shaped by Holocene floods. In some places, Holocene landforms such as landslides, tributary fans, and coastal dunes are mapped that extend outside of the modern floodplain. This map is not a floodplain hazard map or delineation of actual flood boundaries. Although wetlands are included in the Classification, they are based on different criteria than jurisdictional wetlands. The extent of mapping may differ from the actual limit of tidal influence.

  7. Columbia River Estuary Ecosystem Classification Geomorphic Catena

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub-catena". The extent of detailed mapping is the interpreted Holocene geologic floodplain of the tidal Columbia River and its tributaries to the estimated head of tide. The extent of this dataset also includes tributary valleys that are not mapped in detail. The upstream extents of tributary valleys are an estimation of the limit of Columbia River influence and are for use as containers in future analyses. The geologic floodplain is the geomorphic surface that is actively accumulating sediment through occasional overbank deposition. Most features within the geologic floodplain are considered to be formed during the recent (Holocene-epoch) climatic regime. There are bedrock and pre-Holocene sedimentary deposits included where they are surrounded by Holocene sediment accumulations or have been shaped by Holocene floods. In some places, Holocene landforms such as landslides, tributary fans, and coastal dunes are mapped that extend outside of the modern floodplain. This map is not a floodplain hazard map or delineation of actual flood boundaries. Although wetlands are included in the Classification, they are based on different criteria than jurisdictional wetlands. The extent of mapping may differ from the actual limit of tidal influence.

  8. Hydrodynamic controls on oxygen dynamics in a riverine salt wedge estuary, the Yarra River estuary, Australia

    NASA Astrophysics Data System (ADS)

    Bruce, L. C.; Cook, P. L. M.; Teakle, I.; Hipsey, M. R.

    2014-04-01

    Oxygen depletion in coastal and estuarine waters has been increasing rapidly around the globe over the past several decades, leading to decline in water quality and ecological health. In this study we apply a numerical model to understand how salt wedge dynamics, changes in river flow and temperature together control oxygen depletion in a micro-tidal riverine estuary, the Yarra River estuary, Australia. Coupled physical-biogeochemical models have been previously applied to study how hydrodynamics impact upon seasonal hypoxia; however, their application to relatively shallow, narrow riverine estuaries with highly transient patterns of river inputs and sporadic periods of oxygen depletion has remained challenging, largely due to difficulty in accurately simulating salt wedge dynamics in morphologically complex areas. In this study we overcome this issue through application of a flexible mesh 3-D hydrodynamic-biogeochemical model in order to predict the extent of salt wedge intrusion and consequent patterns of oxygen depletion. The extent of the salt wedge responded quickly to the sporadic riverine flows, with the strength of stratification and vertical density gradients heavily influenced by morphological features corresponding to shallow points in regions of tight curvature ("horseshoe" bends). The spatiotemporal patterns of stratification led to the emergence of two "hot spots" of anoxia, the first downstream of a shallow region of tight curvature and the second downstream of a sill. Whilst these areas corresponded to regions of intense stratification, it was found that antecedent conditions related to the placement of the salt wedge played a major role in the recovery of anoxic regions following episodic high flow events. Furthermore, whilst a threshold salt wedge intrusion was a requirement for oxygen depletion, analysis of the results allowed us to quantify the effect of temperature in determining the overall severity and extent of hypoxia and anoxia. Climate warming scenarios highlighted that oxygen depletion is likely to be exacerbated through changes in flow regimes and warming temperatures; however, the increasing risk of hypoxia and anoxia can be mitigated through management of minimum flow allocations and targeted reductions in organic matter loading. A simple statistical model (R2 > 0.65) is suggested to relate riverine flow and temperature to the extent of estuary-wide anoxia.

  9. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2009

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Borde, Amy B.; Bryson, Amanda J.; Cameron, April; Coleman, Andre M.; Corbett, C.; Dawley, Earl M.; Ebberts, Blaine D.; Kauffman, Ronald; Roegner, G. Curtis; Russell, Micah T.; Silva, April; Skalski, John R.; Thom, Ronald M.; Vavrinec, John; Woodruff, Dana L.; Zimmerman, Shon A.

    2010-10-26

    This is the sixth annual report of a seven-year project (2004 through 2010) to evaluate the cumulative effects of habitat restoration actions in the lower Columbia River and estuary (LCRE). The project, called the Cumulative Effects Study, is being conducted for the U.S. Army Corps of Engineers Portland District (USACE) by the Marine Sciences Laboratory of the Pacific Northwest National Laboratory (PNNL), the Pt. Adams Biological Field Station of the National Marine Fisheries Service (NMFS), the Columbia River Estuary Study Taskforce (CREST), and the University of Washington. The goal of the Cumulative Effects Study is to develop a methodology to evaluate the cumulative effects of multiple habitat restoration projects intended to benefit ecosystems supporting juvenile salmonids in the 235-km-long LCRE. Literature review in 2004 revealed no existing methods for such an evaluation and suggested that cumulative effects could be additive or synergistic. From 2005 through 2009, annual field research involved intensive, comparative studies paired by habitat type (tidal swamp versus marsh), trajectory (restoration versus reference site), and restoration action (tidegate replacement vs. culvert replacement vs. dike breach).

  10. Modelling of cohesive sediment dynamics in tidal estuarine systems: Case study of Tagus estuary, Portugal

    NASA Astrophysics Data System (ADS)

    Franz, G.; Pinto, L.; Ascione, I.; Mateus, M.; Fernandes, R.; Leito, P.; Neves, R.

    2014-12-01

    Cohesive sediment dynamics in estuarine systems is a major issue in water quality and engineering problems. Numerical models can help to assess the complex dynamics of cohesive sediments, integrating the information collected in monitoring studies. Following a numerical approach we investigated the main factors that influence the cohesive sediment dynamics in an estuarine system composed of large mudflats (Tagus estuary, Portugal). After a spin up period of the bottom layer and considering the combined effect of waves and currents on the bottom shear stress, the dynamics of cohesive sediment during the fortnightly and daily erosion-sedimentation cycle was properly reproduced by the model. The results of cohesive suspended sediments were validated with data from sixteen monitoring stations located along the estuary and turbidity data measured by two multiparametric probes. The hydrodynamics were previously validated by harmonic analysis and with ADCP data. Although tidal currents are the major cause of cohesive sediment erosion, the results suggest that wind waves also play an important role. The simulated sediment mass involved in the fortnightly tidal cycle was in the same order of magnitude of the annual load from the rivers, as observed in previous studies based on field data.

  11. A DATA SYSTEM FOR INTEGRATING DATA FROM LANDSCAPES, STREAMS AND ESTUARIES

    EPA Science Inventory

    Estuaries are natural integrators of substances and processes that occur internally and externally (watersheds, ocean, atmosphere). Watershed activities that contribute fresh water, nutrients, contaminants, and suspended solids have a strong effect on the health of estuaries. Res...

  12. CLASSIFYING OREGON ESTUARIES BY HABITAT: ANALYSIS OF EXISTING DATA AND A PROPOSAL FOR A PILOT STUDY

    EPA Science Inventory

    Because many estuarine resources are linked to benthic habitats, classification of estuaries by habitat types may prove a relevant approach for grouping estuaries with similar ecological values and vulnerability to landscape alterations. As a first step, we evaluated whether pub...

  13. Alternate shield material feasibility

    SciTech Connect

    Specht, E.R.; Levitt, L.B.

    1984-04-01

    The feasibility and cost/benefit of using materials other than stainless steel for in-vessel neutron shielding in large LMFBRs were investigated. Canned vibratorally compacted B/sub 4/C powder shields were found to be much more economical than stainless steel (a savings of $1.1M in loop plant designs and $9.4M in pool plant designs). The helium gas pressure buildup in B/sub 4/C shields placed around LMFBR in-vessel components (direct reactor heat exchangers in a loop reactor and intermediate heat exchangers in a pool reactor) would only be 0.04 atm after 40 y of reactor operation (with 80% dense powder). The irradiation-induced swelling of the B/sub 4/C would only be 0.002%. No adverse reactor impact would occur if the B/sub 4/C escaped from the B/sub 4/C shields.

  14. Sediment balance of intertidal mudflats in a macrotidal estuary

    NASA Astrophysics Data System (ADS)

    lafite, R.; Deloffre, J.; Lemoine, M.

    2012-12-01

    Intertidal area contributes widely to fine-grained sediment balance in estuarine environments. Their sedimentary dynamics is controlled by several forcing parameters including tidal range, river flow and swell, affected by human activities such as dredging, construction or vessels traffic leading to modify sediment transport pattern. Although the estuarine hydrodynamics is well documented, the link between forcing parameters and these sedimentary processes is weakly understood. One of the main reasons is the difficulty to integrate spatial (from the fluvial to the estuary mouth) and temporal (from swell in seconds to pluriannual river flow variability) patterns. This study achieved on intertidal mudflats distributed along the macrotidal Seine estuary (France) aims (i) to quantify the impact of forcing parameters on each intertidal area respect to its longitudinal position in the estuarine system and (ii) to assess the fine-grained sediment budget at estuarine scale. The Seine estuary is a macrotidal estuary developed over 160 km up the upstream limit of tidal wave penetration. With an average river flow of 450m3.s-1, 80% of the Suspended Particles Matter (SPM) annual flux is discharged during the flood period. In the downstream part, the Seine estuary Turbidity Maximum (TM) is the SPM stock located near the mouth. During their transfer toward the sea, the fine particles can be trapped in (i) the intertidal mudflats; preferential areas characterized by low hydrodynamics and generally sheltered of the tidal dominant flow, the main tidal current the Seine River and (ii) the TM. The Seine estuary is an anthropic estuary in order to secure navigation: one consequence of these developments is the tidal bore disappearance. Along the macrotidal Seine estuary hydrodynamics features and sedimentary fluxes were followed during at least 1 year using respectively Acoustic Doppler Velocimeter, Optical BackScatter and altimeter. Results in the fluvial estuary enhance the role of hydrological cycle that lead to (i) an increased mean water level and (ii) provide SPM from the continental area. This feature leads to significant accretion over intertidal area. In the middle and marine estuary the TM is the main SPM supplier. In these parts of the estuary deposition over these intertidal area is driven by (i) tidal cycle in particular fortnightly cycle link to maximum TM resuspension during (strongest) spring tide and (ii) TM location controlled by river inflow that varies following an annual and inter-annual variability. Outside sedimentation period, the erosion is driven by the combination of (i) progressive erosion driven by fortnightly cycle and (ii) sudden erosion controlled either by wave or boat generated waves respectively at the mouth and in the middle/upper estuary. This last is reinforced by the rheological characteristics of deposit that correspond to fluid/low consolidated mud. During most of the year, the Seine estuary mudflats record an erosion pattern. Significant and intensive sedimentation only occurs few days per year. This pattern is linked to highly variable hydrodynamics conditions (bottom shear stress ranging from 0.5 to 5 N.m-2) that control the sediment supply availability. In this infilling macrotidal anthropized system mudflats are close to equilibrium with an annual rate ranging between +/- 5cm.yrs-1: they act as temporal storage area of fined-grained sediments.

  15. Horizontal distribution and population dynamics of the dominant mysid Hyperacanthomysis longirostris along a temperate macrotidal estuary (Chikugo River estuary, Japan)

    NASA Astrophysics Data System (ADS)

    Suzuki, Keita W.; Nakayama, Kouji; Tanaka, Masaru

    2009-08-01

    The estuarine turbidity maximum (ETM) that develops in the lower salinity areas of macrotidal estuaries has been considered as an important nursery for many fish species. Mysids are one of the dominant organisms in the ETM, serving as a key food source for juvenile fish. To investigate the horizontal distribution and population dynamics of dominant mysids in relation to the fluctuation of physical conditions (temperature, salinity, turbidity, and freshwater discharge), we conducted monthly sampling (hauls of a ring net in the surface water) along the macrotidal Chikugo River estuary in Japan from May 2005 to December 2006. Hyperacanthomysis longirostris was the dominant mysid in the estuary, usually showing peaks of density and biomass in or close to the ETM (salinity 1-10). In addition, intra-specific differences (life-cycle stage, sex, and size) in horizontal distribution were found along the estuary. Larger males and females, particularly gravid females, were distributed upstream from the center of distribution where juveniles were overwhelmingly dominant. Juveniles increased in size toward the sea in marked contrast with males and females. The findings suggest a possible system of population maintenance within the estuary; gravid females release juveniles in the upper estuary, juveniles grow during downstream transport, young males and females mature during the upstream migration. Density and biomass were primarily controlled by seasonal changes of temperature, being high at intermediate temperatures (ca. 15-25 C in late spring and fall) and being low at the extreme temperatures (ca. 10 C in midwinter and 30 C in midsummer). High density (up to 666 ind. m -3) and biomass (up to 168 mg dry weight m -3) of H. longirostris were considered to be comparable with those of copepods in the estuary.

  16. Dynamics of intertidal flats in the Loire estuary

    NASA Astrophysics Data System (ADS)

    Kervella, Stephane; Sottolichio, Aldo; Bertier, Christine

    2014-05-01

    Tidal flats form at the edges of many tidal estuaries, and are found in broad climatic regions. Their evolution plays a fundamental role in maintaining the morphodynamic equilibrium of an estuary. The Loire estuary is one of the largest macrotidal systems of the french atlantic coast. Since 200 years, its geometry has been drastically modified through channeling, deepening, embanking, infilling of secondary channels, etc. These works altered many intertidal areas. In the recent years, efforts for the rectification of the morphology have been made in order to restore the ecology of the estuary. In this context, it is crucial to better understand the dynamics of intertidal flats, still poorly understood in this estuary. The aim of this work is to analyse a series of original observations conducted for the first time in two intertidal flats of the central Lore estuary between 2008 and 2010. The tidal flats are situated in the northern bank, at 12 and 17 km upstream from the mouth respectively. Six Altus altimeters were deployed at two cross shore transects, measuring continuously and at a high-frequency bed altimetry and water level, providing information on tide and waves. At the semi-diurnal tidal scale, the surficial sediment of intertidal flats is permanently mobilized. Altimetry variations are low, and their amplitude varies as a function of tides and river flow. At the scale of several months, the sedimentation is controlled by the position of the turbidity maximum (and therefore by the river flow) and also by the tidal amplitude. During low river flow periods, altimetry variations are only due to tidal cycles. During decaying tides, suspended sediment settle mainly on the lower part of the tidal flats, forming fluid mud layers of several cm thick, which can consolidate rapidly; under rising tides, the increasing of tidal currents promotes erosion. During periods of high river flow, the turbidity maximum shifts to the lower estuary. The higher suspended sediment concentration increases deposition and erosion rates, especially in the lower parts of the flats, where continuous sedimentary accretion is favoured by the proximity of the channel. During this period, reinforcement of current veolocities limits deposition in the central and high portion of the flats, where erosion is enhanced. The first rivers floods remove fluid mud in the upper estuary, previously deposited during the dry season, which is transported seawards. The transported suspended sediment settles massively in the lower parts of the flats and in the channels. The deposited mud is eroded a few days later. These results provide useful information to better understand the dynamics of the Loire estuary, as well as they give in situ data to be compared with numerical modelling.

  17. Antibiotic Resistance of Escherichia coli Serotypes from Cochin Estuary

    PubMed Central

    Sukumaran, Divya P.; Durairaj, Srinivasan; Abdulla, Mohamed Hatha

    2012-01-01

    This study aimed at detecting the prevalence of antibiotic-resistant serotypes of Escherichia coli in Cochin estuary, India. E. coli strains were isolated during the period January 2010–December 2011 from five different stations set at Cochin estuary. Water samples from five different stations in Cochin estuary were collected on a monthly basis for a period of two years. Isolates were serotyped, antibiogram-phenotyped for twelve antimicrobial agents, and genotyped by polymerase chain reaction for uid gene that codes for β-D-glucuronidase. These E. coli strains from Cochin estuary were tested against twelve antibiotics to determine the prevalence of multiple antibiotic resistance among them. The results revealed that more than 53.33% of the isolates were multiple antibiotic resistant. Thirteen isolates showed resistance to sulphonamides and two of them contained the sul 1 gene. Class 1 integrons were detected in two E. coli strains which were resistant to more than seven antibiotics. In the present study, O serotyping, antibiotic sensitivity, and polymerase chain reaction were employed with the purpose of establishing the present distribution of multiple antibiotic-resistant serotypes, associated with E. coli isolated from different parts of Cochin estuary. PMID:23008708

  18. Nitrogen and phosphorus budgets of the Changjiang River estuary

    NASA Astrophysics Data System (ADS)

    Li, Xiang'an; Yu, Zhiming; Song, Xiuxian; Cao, Xihua; Yuan, Yongquan

    2011-07-01

    Eutrophication has emerged as a key environmental problem in Chinese coastal waters, especially in the Changjiang (Yangtze) River estuary. In this area, large nutrient inputs result in frequent harmful algal blooms and serious hypoxia in bottom waters. Four cruises were made in the estuary in 2006 to assess the concentration and distribution of dissolved inorganic nitrogen (DIN) and phosphorus (DIP). The concentration of DIN decreased gradually in a linear relationship with salinity from the river mouth to outer waters, while DIP was relatively more dispersed. A modified box budget method was used to estimate nutrient fluxes in the estuary and its adjacent waters. Water and nutrient budgets as well as primary production and denitrification rates were estimated from the box budget model. Estimated water residence time in the estuary was about 11 d. The turbid mixing zone released 33% of DIN and 49% of DIP, while in the adjacent outer sea 17.9 mmol DIN/m2d and 0.36 mmol DIP/m2d were fixed. Dissolved inorganic phosphorus was imported from the deep open sea waters, supporting primary production and population growth in this zone. Net ecosystem production (NEP) was calculated at 38.2 mmol/m2d in the outer estuary and the estimated rate (N-fixation minus denitrification) was negative (1.92 mmol/m2d), implying that a large amount of input nitrogen was taken up by algae and recycled through denitrification in bottom water and sediment.

  19. Sources, Ages, and Alteration of Organic Matter in Estuaries

    NASA Astrophysics Data System (ADS)

    Canuel, Elizabeth A.; Hardison, Amber K.

    2016-01-01

    Understanding the processes influencing the sources and fate of organic matter (OM) in estuaries is important for quantifying the contributions of carbon from land and rivers to the global carbon budget of the coastal ocean. Estuaries are sites of high OM production and processing, and understanding biogeochemical processes within these regions is key to quantifying organic carbon (Corg) budgets at the land-ocean margin. These regions provide vital ecological services, including nutrient filtration and protection from floods and storm surge, and provide habitat and nursery areas for numerous commercially important species. Human activities have modified estuarine systems over time, resulting in changes in the production, respiration, burial, and export of Corg. Corg in estuaries is derived from aquatic, terrigenous, and anthropogenic sources, with each source exhibiting a spectrum of ages and lability. The complex source and age characteristics of Corg in estuaries complicate our ability to trace OM along the river–estuary–coastal ocean continuum. This review focuses on the application of organic biomarkers and compound-specific isotope analyses to estuarine environments and on how these tools have enhanced our ability to discern natural sources of OM, trace their incorporation into food webs, and enhance understanding of the fate of Corg within estuaries and their adjacent waters.

  20. The behavior of dissolved inorganic selenium in the Changjiang Estuary

    NASA Astrophysics Data System (ADS)

    Chang, Yan; Zhang, Jing; Qu, Jianguo; Zhang, Guosen; Zhang, Anyu; Zhang, Ruifeng

    2016-02-01

    To investigate the behavior of inorganic selenium species in the Changjiang Estuary, samples were taken during summer (July 2011) and winter (March 2012). Dissolved inorganic selenium (DISe) concentrations averaged 1.79 nmol/L in summer and 1.24 nmol/L in winter; the average selenite [Se(IV)] to selenate [Se(VI)] ratio [Se(IV)/Se(VI)] was 0.42 in summer and 0.61 in winter. The data show that Se(IV) and Se(VI) concentrations in the estuary behaved strictly conservatively during winter but non-conservatively during summer due to adsorption by suspended particulate matter (SPM) and assimilation by phytoplankton. In addition, the Se concentration distributions in the Changjiang Estuary were controlled by three water masses, each with a specific Se(IV)/Se(VI) ratio "signature": the Changjiang Water input, the Taiwan Warm Current, and the Yellow Sea Coastal Current. The Se(IV) concentrations were related to the nitrate, silicate, and phosphate concentrations in the estuary. The DISe and Se(IV) concentrations were comparable to those found in other coastal regions and estuaries, which were considered to be natural levels.

  1. Persistent organic pollution characterization of sediments in Pearl River estuary.

    PubMed

    Chau, K W

    2006-08-01

    As a byproduct of rapid urbanization and industrial development in the Pearl River estuary of South China, excessive release of various types of persistent toxic substances were conveyed from agricultural, industrial and municipal discharges at upstream section down into the estuary largely via various river outlets. In this paper, a persistent organic pollution (POP) characterization of sediments in the estuary is undertaken. More than one bioavailable toxicants are detected to play active roles in causing toxicity of marine sediments in the estuary. POPs may be transported for long distances to the downstream end of the Pearl River delta region. The data suggests that DDT might still be applied illegally within the region recently and that the prevalent levels of DDTs and HCHs in sediments are likely to pose detrimental biological effects on benthic organisms. The findings have significant implications in order to understand the environmental changes, to determine reasonable ways for future development, and to maintain a sustainable environment in the Pearl River estuary region. PMID:16403562

  2. Metals in sediments and benthic organisms in the Mersey estuary

    NASA Astrophysics Data System (ADS)

    Langston, W. J.

    1986-08-01

    Concentrations of twelve metals were determined in sediments, seaweed ( Fucus vesiculosus), winkles ( Littorina littorea), polychaetes ( Nereis diversicolor), suspension feeding bivalves ( Mytilus edulis, Cerastoderma edule) and deposit feeding bivalves ( Macoma balthica, Scrobicularia plana) collected from the Mersey estuary between April 1980 and June 1984. Sediments and organisms in the Mersey are moderately contaminated with most of the metals measured, but mercury concentrations are consistently higher than in other United Kingdom estuaries. Comparisons with other sites in the North West of England indicate that mercury residues in organisms, though primarily dependent on sediment concentrations, are also influenced by complexation with particulate organic matter which reduces the availability of mercury. The biological availability of arsenic in Mersey sediments is similarly influenced by complexation with iron oxyhydroxides. Nereis diversicolor and Macoma balthica are the most suitable indicator species in terms of abundance and widespread distribution along the estuary, and, for the majority of metals, tissue concentrations increase upstream, reflecting corresponding gradients in sediment contamination. However mid-estuarine peaks for tin, chromium copper and nickel in Nereis indicate more localised inputs to the estuary. Correlations between lead in sediments and organisms are poor; it is suggested that hydrophilic alkyl lead compounds may be the predominant biologically available forms. Progressive reductions in mercury contamination in sediments and mercury and lead in organisms have occurred in recent years, which coincide with efforts to reduce inputs of these metals to teh Mersey estuary.

  3. A Simple Model of Nitrogen Concentration, Throughput, and Denitrification in Estuaries

    EPA Science Inventory

    The Estuary Nitrogen Model (ENM) is a mass balance model that includes calculation of nitrogen losses within bays and estuaries using system flushing time. The model has been used to demonstrate the dependence of throughput and denitrification of nitrogen in bays and estuaries on...

  4. PEER REVIEW OF PECONIC ESTUARY PROGRAM HYDRODYNAMIC AND WATER QUALITY (EUTROPHICATION) MODEL

    EPA Science Inventory

    The Peconic Estuary is located on the eastern end of Long Island, New York. Under the Federal Clean Water Act, the Peconic Estuary was named an "Estuary of National Significance" in 1992. Because of its high concentration of rare, threatened and endangered species and habitats,...

  5. 33 CFR 165.1190 - Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., Oakland Estuary, Alameda, CA. 165.1190 Section 165.1190 Navigation and Navigable Waters COAST GUARD... § 165.1190 Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA. (a) Location. The following area is a security zone: All navigable waters of the Oakland Estuary, California, from the surface...

  6. 33 CFR 165.1190 - Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Oakland Estuary, Alameda, CA. 165.1190 Section 165.1190 Navigation and Navigable Waters COAST GUARD... § 165.1190 Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA. (a) Location. The following area is a security zone: All navigable waters of the Oakland Estuary, California, from the surface...

  7. Proliferation of dinoflagellates in Kochi estuary, Kerala.

    PubMed

    Kumar, M Ratheesh; Vishnu, S Raj; Sudhanandh, V S; Faisal, A K; Shibu, R; Vimexen, V; Ajmal, K; Aneesh, K S; Antony, Sibin; Krishnan, Anoop K

    2014-09-01

    Phytoplankton community structure and dynamics of Kochi estuary (bar mouth) have been studied seasonally. Three seasonal samplings namely pre-monsoon, monsoon and post-monsoon were made, and a wide variation was observed in phytoplankton community with respect to nutrients and other physicochemical parameters. Contrary to other seasons, dinoflagellate cell density increased during pre-monsoon season though species diversity was less pronounced (D > 0.15). Peridinium oceanicum was the dominant dinoflagellate during pre-monsoon season. Significant fluctuation in three principal nutrients namely total nitrogen, total phosphorous and silicate were observed during pre-monsoon (TP < 1.8 micromol l(-1), TN > 40 micromol l(-1) and SiO4 < 20 micromol l(-1)) season as compared to monsoon season (TP > 3.20 micromol l(-1), TN < 20 micromol l(-1) and SiO4 > 27 micromol l(-1)). Salinity values were also found to be high during pre-monsoon ( > 25 psu). Study suggests that variation in salinity and nutrient concentration during transition of seasons could result in succession of species, thereby causing change in phytoplankton community structure. High salinity and nitrogen values along with low values of silicate and phosphorous resulted in proliferation of dinoflagellates during pre-monsoon season. PMID:25204062

  8. Numerical modeling of circulation in high-energy estuaries: A Columbia River estuary benchmark

    NASA Astrophysics Data System (ADS)

    Kärnä, Tuomas; Baptista, António M.; Lopez, Jesse E.; Turner, Paul J.; McNeil, Craig; Sanford, Thomas B.

    2015-04-01

    Numerical modeling of three-dimensional estuarine circulation is often challenging due to complex flow features and strong density gradients. In this paper the skill of a specific model is assessed against a high-resolution data set, obtained in a river-dominated mesotidal estuary with autonomous underwater vehicles and a shipborne winched profiler. The measurements provide a detailed view of the salt wedge dynamics of the Columbia River estuary. Model skill is examined under contrasting forcing conditions, covering spring freshet and autumn low flow conditions, as well as spring and neap tides. The data set provides a rigorous benchmark for numerical circulation models. This benchmark is used herein to evaluate an unstructured grid circulation model, based on linear finite element and finite volume formulations. Advection of momentum is treated with an Eulerian-Lagrangian scheme. After the model's sensitivity to grid resolution and time step is examined, a detailed skill assessment is provided for the best model configuration. The simulations reproduce the timing and tidal asymmetry of salinity intrusion. Sharp density gradients, however, tend to be smoothed out affecting vertical mixing and gravitational circulation. We show that gravitational salt transport is underestimated in the model, but is partially compensated through tidal effects. The discrepancy becomes most pronounced when the stratification is strongest, i.e., under high river discharge and neap tide conditions.

  9. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY09 Annual Report

    SciTech Connect

    Johnson, Gary E.

    2009-10-22

    This document is the annual report for fiscal year 2009 (FY09) for the project called Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort developed by the Action Agencies (Bonneville Power Administration [BPA], U.S. Army Corps of Engineers [Corps or USACE], U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS).

  10. Feasibility of remote sensing benthic microalgae

    NASA Technical Reports Server (NTRS)

    Zingmark, R. G.

    1979-01-01

    Results of data analyses from multispectral scanning data are presented. The data was collected in July 1977 for concentration of chlorophyll in benthic microalgae (mainly diatoms) on an estuary mudflat.

  11. Tribal Utility Feasibility Study

    SciTech Connect

    Engel, R. A.; Zoellick, J. J.

    2007-06-30

    The Schatz Energy Research Center (SERC) assisted the Yurok Tribe in investigating the feasibility of creating a permanent energy services program for the Tribe. The original purpose of the DOE grant that funded this project was to determine the feasibility of creating a full-blown Yurok Tribal electric utility to buy and sell electric power and own and maintain all electric power infrastructure on the Reservation. The original project consultant found this opportunity to be infeasible for the Tribe. When SERC took over as project consultant, we took a different approach. We explored opportunities for the Tribe to develop its own renewable energy resources for use on the Reservation and/or off-Reservation sales as a means of generating revenue for the Tribe. We also looked at ways the Tribe can provide energy services to its members and how to fund such efforts. We identified opportunities for the development of renewable energy resources and energy services on the Yurok Reservation that fall into five basic categories: • Demand-side management – This refers to efforts to reduce energy use through energy efficiency and conservation measures. • Off-grid, facility and household scale renewable energy systems – These systems can provide electricity to individual homes and Tribal facilities in areas of the Reservation that do not currently have access to the electric utility grid. • Village scale, micro-grid renewable energy systems - These are larger scale systems that can provide electricity to interconnected groups of homes and Tribal facilities in areas of the Reservation that do not have access to the conventional electric grid. This will require the development of miniature electric grids to serve these interconnected facilities. • Medium to large scale renewable energy development for sale to the grid – In areas where viable renewable energy resources exist and there is access to the conventional electric utility grid, these resources can be developed and sold to the wholesale electricity market. • Facility scale, net metered renewable energy systems – These are renewable energy systems that provide power to individual households or facilities that are connected to conventional electric utility grid.

  12. The stirling engine for vehicle propulsion

    NASA Technical Reports Server (NTRS)

    Kuhlman, P.

    1978-01-01

    The performance data of experimental Stirling engines are considered along with questions of exhaust-gas composition, engine noise, engine volume and weight, engine control, and the engine-starting process. The Stirling engine can use practically any liquid or gaseous fuel for its operation. It is found that technically a use of the Stirling engine in motor vehicles is feasible. Economic questions related to an introduction of the Stirling engine are discussed along with possible new developments which could improve the economic situation in favor of a use of Stirling engine.

  13. Bin Set 1 Calcine Retrieval Feasibility Study

    SciTech Connect

    R. D. Adams; S. M. Berry; K. J. Galloway; T. A. Langenwalter; D. A. Lopez; C. M. Noakes; H. K. Peterson; M. I. Pope; R. J. Turk

    1999-10-01

    At the Department of Energy's Idaho Nuclear Technology and Engineering Center, as an interim waste management measure, both mixed high-level liquid waste and sodium bearing waste have been solidified by a calculation process and are stored in the Calcine Solids Storage Facilities. This calcined product will eventually be treated to allow final disposal in a national geologic repository. The Calcine Solids Storage Facilities comprise seven ''bit sets.'' Bin Set 1, the first to be constructed, was completed in 1959, and has been in service since 1963. It is the only bin set that does not meet current safe-shutdown earthquake seismic criteria. In addition, it is the only bin set that lacks built-in features to aid in calcine retrieval. One option to alleviate the seismic compliance issue is to transport the calcine from Bin Set 1 to another bin set which has the required capacity and which is seismically qualified. This report studies the feasibility of retrieving the calcine from Bi n Set 1 and transporting it into Bin Set 6 which is located approximately 650 feet away. Because Bin Set 1 was not designed for calcine retrieval, and because of the high radiation levels and potential contamination spread from the calcined material, this is a challenging engineering task. This report presents preconceptual design studies for remotely-operated, low-density, pneumatic vacuum retrieval and transport systems and equipment that are based on past work performed by the Raytheon Engineers and Constructors architectural engineering firm. The designs presented are considered feasible; however, future development work will be needed in several areas during the subsequent conceptual design phase.

  14. Effects of heavy metal contamination on the macrobenthic fauna in estuaries: the case of the Seine estuary.

    PubMed

    Dauvin, Jean-Claude

    2008-01-01

    Heavy metal contamination levels are generally higher in estuaries than in the open sea. Some estuaries, the Seine estuary for example, have particularly high pollution levels of metals, yet continue to support a very high benthic biomass and remain quite productive. Measurements of sediment contamination are highly variable due to diverse chemical analysis methods, sediments origin and sources of contaminants found in the estuaries. Salinity appears to be the principal factor controlling contaminant distribution in the sediment and the overlying and/or interstitial waters; it also affects the bioavailability of contaminants in estuarine sediments. Of course, the response to contaminants varies greatly among species and assemblages. Trace metals explain only a small part of the variation in benthic community structure. Some species, such as the shrimp Crangon crangon, appears vulnerable to metal pollution, while other species, such as Scrobicularia plana, are able to tolerate quite high levels of cadmium in their tissue. This paper demonstrates the wide variability of benthic responses to contamination, which is probably due to the high spatio-temporal heterogeneity of the estuary. To reduce the problems due the heterogeneity and variability observed to date in the available results, it will be necessary to encourage integrated estuarine studies, in which sedimentologists, chemists, and biologists work together on the same campaigns at the same sites. PMID:18045624

  15. Impact of the Clean Water Act on the levels of toxic metals in urban estuaries: The Hudson River estuary revisited

    SciTech Connect

    Sanudo-Wilhelmy, S.A.; Gill, G.A.

    1999-10-15

    To establish the impact of the Clean Water Act on the water quality of urban estuaries, dissolved trace metals and phosphate concentrations were determined in surface waters collected along the Hudson River estuary between 1995 and 1997 and compared with samples collected in the mid-1970s by Klinkhammer and Bender. The median concentrations along the estuary have apparently declined 36--56% for Cu, 55--89% for Cd, 53--85% for Ni, and 53--90% for Zn over a period of 23 years. These reductions appear to reflect improvements in controlling discharges from municipal and industrial wastewater treatment plants since the Clean Water Act was enacted in 1972. In contrast, levels of dissolved nutrients (PO{sub 4}) have remained relatively constant during the same period of time, suggesting that wastewater treatment plant improvements in the New York/New Jersey Metropolitan area have not been as effective at reducing nutrient levels within the estuary. While more advanced wastewater treatment could potentially reduce the levels of Ag and PO{sub 4} along the estuary, these improvements would have a more limited effect on the levels of other trace metals.

  16. The buffering capacity of a small estuary on nutrient fluxes originating from its catchment (Leyre estuary, SW France)

    NASA Astrophysics Data System (ADS)

    Canton, Mathieu; Anschutz, Pierre; Poirier, Dominique; Chassagne, Romain; Deborde, Jonathan; Savoye, Nicolas

    2012-03-01

    This work studied the impact of a small estuary (a 4 km-long estuary, at the interface between the Leyre River and the Arcachon lagoon, SW France) with a short flushing time on continental nutrient loads to a coastal lagoon. While large estuaries are known to modify the nutrient load of rivers to the coast, the impact on continental fluxes of a short salinity gradient from small coastal rivers is rarely studied. A survey of nutrient and dissolved organic matter concentration, particulate phosphorus speciation and particulate organic matter (POM) concentration and characteristics (C:N ratio and particulate organic carbon ?13C) showed that the estuarine behaviour varied throughout the year. The autochthonous primary production was a sink of dissolved N, P and Si in spring. During this period, the continental load of dissolved nitrogen was reduced by about 1/3 and phosphorus was totally consumed by estuarine processes. Nutrient recycling occurred in summer with ammonium production although this source was low in comparison with continental fluxes of nitrogen. The phosphorus concentration was dominated by the iron oxides-bound fraction. Contrary to large estuaries, the desorption of particulate phosphorus was not a source of dissolved phosphorus. Our results showed that estuarine processes impacted the net nutrient fluxes during productive periods, although estuarine residence time was very short. Passive transport with conservative mixing of nutrient was observed in autumn and winter. The non-conservative behaviour of small estuaries must be taken into account for nutrient mass balance calculation in lagoon.

  17. The MRIS feasibility study

    NASA Technical Reports Server (NTRS)

    Neece, Robert T.; Cross, Aubrey E.; Schrader, James H.

    1993-01-01

    The Microwave Reflectometer Ionization Sensor (MRIS) is an instrument being developed for use in detecting and ranging of electron density layers in the reentry plasma of a space transfer vehicle. The rationale for the selection of the Double Sideband Suppressed Carrier (DSBSC) system used in the feasibility study for the MRIS is presented. A 25 GHz single-oscillator system and a 220 GHz double-oscillator system are described. The 25 GHz system was constructed and tested in the laboratory and test results are presented. As developed, the system employs a sideband spacing of 160 MHz. Based on an estimated electromagnetic wave velocity in the plasma, a round-trip phase shift measurement accuracy of +/- 7.6 degrees was required for the desired +/- 1/2 cm distance measurement accuracy. The interaction of parallel ground and reflecting planes produces interference that prevents the basic DSBSC system from meeting the accuracy goal so a frequency modulation was added to the system to allow averaging of the measured phase deviation. With an FM deviation of +/- 1 GHz, laboratory measurements were made for distances from 5 to 61 cm tip free space. Accounting for the plasma velocity factor, 82 percent of the data were equal to or better than the desired accuracy. Based on this measured result a sideband spacing to 250 MHz could be expected to yield data approximately 96 percent within the accuracy goal.

  18. Planetary engineering

    NASA Astrophysics Data System (ADS)

    Pollack, James B.; Sagan, Carl

    Assuming commercial fusion power, heavy lift vehicles and major advances in genetic engineering, the authors survey possible late-21st century methods of working major transformations in planetary environments. Much more Earthlike climates may be produced on Mars by generating low freezing point greenhouse gases from indigenous materials; on Venus by biological conversion of CO2 to graphite, by canceling the greenhouse effect with high-altitude absorbing fine particles, or by a sunshield at the first Lagrangian point; and on Titan by greenhouses and/or fusion warming. However, in our present state of ignorance we cannot guarantee a stable endstate or exclude unanticipated climatic feedbacks or other unintended consequences. Moreover, as the authors illustrate by several examples, many conceivable modes of planetary engineering are so wasteful of scarce solar system resources and so destructive of important scientific information as to raise profound ethical issues, even if they were economically feasible, which they are not. Global warming on Earth may lead to calls for mitigation by planetary engineering, e.g., emplacement and replenishment of anti-greenhouse layers at high altitudes, or sunshields in space. But here especially we must be concerned about precision, stability, and inadvertent side-effects. The safest and most cost-effective means of countering global warming - beyond, e.g., improved energy efficiency, CFC bans and alternative energy sources - is the continuing reforestation of approximately 2 times 107 sq km of the Earth's surface. This can be accomplished with present technology and probably at the least cost.

  19. Planetary engineering

    NASA Technical Reports Server (NTRS)

    Pollack, James B.; Sagan, Carl

    1991-01-01

    Assuming commercial fusion power, heavy lift vehicles and major advances in genetic engineering, the authors survey possible late-21st century methods of working major transformations in planetary environments. Much more Earthlike climates may be produced on Mars by generating low freezing point greenhouse gases from indigenous materials; on Venus by biological conversion of CO2 to graphite, by canceling the greenhouse effect with high-altitude absorbing fine particles, or by a sunshield at the first Lagrangian point; and on Titan by greenhouses and/or fusion warming. However, in our present state of ignorance we cannot guarantee a stable endstate or exclude unanticipated climatic feedbacks or other unintended consequences. Moreover, as the authors illustrate by several examples, many conceivable modes of planetary engineering are so wasteful of scarce solar system resources and so destructive of important scientific information as to raise profound ethical issues, even if they were economically feasible, which they are not. Global warming on Earth may lead to calls for mitigation by planetary engineering, e.g., emplacement and replenishment of anti-greenhouse layers at high altitudes, or sunshields in space. But here especially we must be concerned about precision, stability, and inadvertent side-effects. The safest and most cost-effective means of countering global warming - beyond, e.g., improved energy efficiency, CFC bans and alternative energy sources - is the continuing reforestation of approximately 2 times 107 sq km of the Earth's surface. This can be accomplished with present technology and probably at the least cost.

  20. Origin of carbon in organic matter in the Neva estuary.

    PubMed

    Golubkov, S M; Tiunov, A V

    2015-11-01

    Analysis of the isotopic composition of tissues of representatives of zoobenthos and organic matter of seston have shown that the major part of carbon participating in the biological turnover in the ecosystem of the upper part of the Neva estuary is of terrestrial origin. Obviously, it is discharged from the lake drainage area to the Lake Ladoga-Neva-Neva estuary system. The results have revealed an important role in aquatic ecosystems of the humid zone of allochthonous humic substances creating a supplementary stock of nutrients and enhancing the productivity of ecosystems. Detailed investigations of the role of various forms of allochthonous organic compounds of terrestrial origin are necessary for elaboration of efficient measures for alleviation of eutrophication of the Neva estuary. PMID:26725237

  1. Initial growth of phytoplankton in turbid estuaries: A simple model

    NASA Astrophysics Data System (ADS)

    de Swart, H. E.; Schuttelaars, H. M.; Talke, S. A.

    2009-01-01

    An idealised model is presented and analysed to gain more fundamental understanding about the dynamics of phytoplankton blooms in well-mixed, suspended sediment dominated estuaries. The model describes the behaviour of subtidal currents, suspended sediments, nutrients and phytoplankton in a channel geometry. The initial growth of phytoplankton and its spatial distribution is calculated by solving an eigenvalue problem. The growth rates depend on the position in the estuary due to along-estuary variations in nutrient concentration and suspended sediment concentration. The model yields an insight into how the onset of blooms in the model depends on physical and biological processes (turbulent mixing, fresh water discharge, light attenuation, imposed nutrient concentrations at the river and sea side). In particular, the model demonstrates that the joint action of spatial variations in turbidity and in nutrients causes the maximum phytoplankton concentrations to occur seaward of the estuarine turbidity maximum.

  2. The geomorphology of UK estuaries: The role of geological controls, antecedent conditions and human activities

    NASA Astrophysics Data System (ADS)

    Pye, Kenneth; Blott, Simon J.

    2014-10-01

    This paper provides an overview of the geomorphological characteristics of UK estuaries and the factors which control them. Many of the features included in previous classifications of UK estuaries are not true estuaries since they do not possess significant river influence. The features considered in this paper to be 'true' estuaries are divided into 'restricted entrance' and 'unrestricted entrance' types on the grounds that the size and geometry of the estuary mouth exerts a critical influence on water levels, tidal currents, wave action, sediment transport and morphological evolution. An estuary which has a wide mouth, narrows and becomes shallower towards the head is likely to be flood dominated, especially if it has a large tidal range, whereas an estuary which has a narrow mouth and widens and/or becomes deeper towards the head is more likely to display ebb dominance, especially if it has a relatively small tidal range. Wide-mouthed estuaries are influenced to a greater degree by wave processes than estuaries with a narrow mouth. Previous authors have hypothesised that estuaries may maintain a state of dynamic equilibrium through alternating periods of flood and ebb dominance, but it is concluded that there is presently no substantive evidence to support this hypothesis. UK estuaries have been affected to varying degrees by embanking, land claim, dredging, sea wall breaching and managed realignment. Some estuaries have adjusted quickly to such perturbations, but others continue to show progressive change, either sedimentary infilling or erosion and sediment loss. The quantification of estuary morphometry, identification of change over time, and testing of hypotheses regarding the morphodynamics and stability of estuaries requires adequate bathymetric/topographic, hydrodynamic and sediment data. At present, such data are available for relatively few UK estuaries.

  3. Radium isotopes in the Orinoco estuary and Eastern Caribbean Sea

    SciTech Connect

    Moore, W.S.; Todd, J.F. )

    1993-02-15

    Radium isotopes provide a means of identifying the source of freshened waters in the ocean and determining the time elapsed since these waters were in the estuary. The authors present evidence that during April, waters from the Amazon mixing zone pass within 50 km of the mouth of the Orinoco River. These Amazon waters are characterized by a lower [sup 228]Ra/[sup 226]Ra activity ratio (AR) than are waters from the Orinoco at similar salinities. During autumn, the increased discharge of the Orinoco displaces the freshened Amazon waters seaward, yet the two can be distinguished clearly. Within the Caribbean Sea, waters of Orinoco origin carry a characteristic radium signature including excess activities of [sup 224]Ra. This isotope may be used to estimate the time elapsed since the waters were removed from contact with sediments. Current speeds based on [sup 224]Ra dating ranged from 15 to 33 cm/s during April. The radium isotopes also provide an assessment of sediment mixing in the estuary. During low discharge (April), considerable mixing of older sediment by physical or biological processes or dredging maintained high activities of [sup 228]Ra in the estuary and produced the highest [sup 228]Ra/[sup 226]Ra AR's yet measured in any estuary. During high discharge (September), a large fraction of the [sup 228]Ra was derived from desorption from fresh sediment rather than mixing of older sediments. Activities of [sup 224]Ra were high in the estuary during both high and low discharge, indicating that considerable mixing of recently introduced sediment must occur during each period. During April, [sup 224]Ra and [sup 228]Ra activities in the water were about equal, indicating that most of the sediment being resuspended had been stored in the estuary long enough to reestablish radioactive equilibrium in the [sup 232]Th decay series (i.e., 20 years). 19 refs., 11 figs., 3 tabs.

  4. Spring climate and salinity in the San Francisco Bay Estuary

    USGS Publications Warehouse

    Cayan, Daniel R.; Peterson, David H.

    1993-01-01

    Salinity in the San Francisco Bay Estuary almost always experiences its yearly maximum during late summer, but climate variability produces marked interannual variations. The atmospheric circulation pattern impacts the estuary primarily through variations of runoff from rainfall and snowmelt from the Sierra Nevada and, secondarily, through variations in the near-surface salinity in the coastal ocean. While winter precipitation is the primary influence upon salinity in the estuary, spring climate variations also contribute importantly to salinity fluctuations. Spring atmospheric circulation influences both the magnitude and the timing of freshwater flows, through anomalies of precipitation and temperature. To help discriminate between the effects of these two influences, the record is divided into subsets according to whether spring conditions in the region are cool and wet, warm and wet, cool and dry, or warm and dry. Warm springs promote early snowmelt-driven flows, and cool springs result in delayed flows. In addition to effects of winter and spring climate variability operating on the watershed, there are more subtle effects that are transmitted into the estuary from the coastal ocean. These influences are most pronounced in cool and dry springs with high surface salinity (SS) in the coastal ocean versus cool and wet springs with low SS in the coastal ocean. A transect of SS records at stations from the mouth to the head of the bay suggests that the coastal ocean anomaly signal is attenuated from the mouth to the interior of the estuary. In contrast, a delayed, postsummer signal caused by winter and spring runoff variations from the upstream watershed are most pronounced at the head of the estuary and attenuate toward the mouth.

  5. Mud transport in the Microtidal San Jacinto Estuary

    NASA Astrophysics Data System (ADS)

    Salehi, M.; Strom, K. B.

    2012-12-01

    The overall objective of this research is to better understand the sediment transport processes in the microtidal San Jacinto Estuary (near Houston, TX) under variable hydrologic conditions. A numerical modeling approach is selected to answer the main question of; how will changes in freshwater input change the sedimentation pattern of the region? In this computational work, no new numerical method or code is developed, but rather an existing technology (MIKE 3D developed by DHI) is used to build a virtual San Jacinto Estuary laboratory where boundary conditions could be applied and altered to the domain to observe the general functional response of the system. Two synthetic freshwater inflows, simulating dry and wet conditions, were used in the numerical modeling experiments. Simulations showed that change in freshwater inflow has major impact on the salinity magnitude within the estuary. In dry conditions, the 5 ppt isohaline traveled all the way upstream of Morgans Point, almost to the confluence of San Jacinto River with Buffalo Bayou. During the extreme wet weather conditions, the 5 ppt isohaline of the surface water was pushed almost as far as Galveston Island. Overall erosion and deposition pattern showed little change between extreme dry and wet years. In general, part of the shallow areas experienced erosion whereas deeper parts of the estuary were under deposition. High freshwater inflow caused around 30% higher deposition in some parts of the channel compared with the low freshwater. Furthermore, examining the mass balance within the whole San Jacinto Estuary showed that around 28% of the input sediment was flushed out during the wet season. But in dry season, not only no sediment left the domain but also it received around 17% of the total available sediment within the estuary from the shelf.

  6. Mud transport in the Microtidal San Jacinto Estuary

    NASA Astrophysics Data System (ADS)

    Salehi, M.

    2013-12-01

    The overall objective of this research is to better understand the sediment transport processes in the microtidal San Jacinto Estuary (near Houston, TX) under variable hydrologic conditions. A numerical modeling approach is selected to answer the main question of; how will changes in freshwater input change the sedimentation pattern of the region? In this computational work, no new numerical method or code is developed, but rather an existing technology (MIKE 3D developed by DHI) is used to build a virtual San Jacinto Estuary laboratory where boundary conditions could be applied and altered to the domain to observe the general functional response of the system. Two synthetic freshwater inflows, simulating dry and wet conditions, were used in the numerical modeling experiments. Simulations showed that change in freshwater inflow has major impact on the salinity magnitude within the estuary. In dry conditions, the 5 ppt isohaline traveled all the way upstream of Morgans Point, almost to the confluence of San Jacinto River with Buffalo Bayou. During the extreme wet weather conditions, the 5 ppt isohaline of the surface water was pushed almost as far as Galveston Island. Overall erosion and deposition pattern showed little change between extreme dry and wet years. In general, part of the shallow areas experienced erosion whereas deeper parts of the estuary were under deposition. High freshwater inflow caused around 30% higher deposition in some parts of the channel compared with the low freshwater. Furthermore, examining the mass balance within the whole San Jacinto Estuary showed that around 28% of the input sediment was flushed out during the wet season. But in dry season, not only no sediment left the domain but also it received around 17% of the total available sediment within the estuary from the shelf.

  7. Hydrology of major estuaries and sounds of North Carolina

    USGS Publications Warehouse

    Giese, G.L.; Wilder, Hugh B.; Parker, Garald G., Jr.

    1985-01-01

    Hydrology-related problems associated with North Carolina 's major estuaries and sounds include contamination of some estuaries with municipal and industrial wastes and drainage from adjacent, intensively farmed areas, and nuisance-level algal blooms. In addition, there is excessive shoaling in some navigation channels, salt-water intrusion into usually fresh estuarine reaches, too high or too-low salinities in nursery areas for various estuarine species, and flood damage due to hurricanes. The Cape Fear River is the only major North Carolina estuary having a direct connection to the sea. Short-term flow throughout most of its length is dominated by ocean tides. Freshwater entering the major estuaries is, where not contaminated, of acceptable quality for drinking with minimum treatment. However, iron concentrations in excess of 0.3 milligrams per liter sometimes occur and water draining from swampy areas along the Coastal Plain is often highly colored, but these problems may be remedied with proper treatment. Nuisance-level algal blooms have been a recurring problem on the lower estuarine reaches of the Neuse, Tar-Pamlico, and Chowan Rivers where nutrients (compounds of phosphorous and nitrogen) are abundant. The most destructive blooms tend to occur in the summer months during periods of low freshwater discharge and relatively high water temperatures. Saltwater intrusion occurs from time to time in all major estuaries except the Roanoke River, where releases from Roanoke Rapids Lake and other reservoirs during otherwise low-flow periods effectively block saline water from the estuary. New shoaling materials found in the lower channelized reaches of the Cape Fear and Northeast Cape Fear Rivers are primarily derived, not from upstream sources, but from nearby shore erosion, from slumping of material adjacent to the dredged channels, from old spoil areas, or from ocean-derived sediments carried upstream by near-bottom density currents.

  8. Aircraft towing feasibility study. Final report

    SciTech Connect

    Not Available

    1980-09-01

    Energy costs and availability are major concerns in most parts of the world. Many ways of increasing energy supply and reducing consumption are being proposed and investigated. One that holds considerable promise is the extended towing of aircraft between airport runways and terminal gate areas with engines shut down. This study provides a preliminary assessment of the constraints on and feasibility of extended aircraft towing. Past aircraft towing experience and the state-of-the-art in towing equipment are reviewed. Safety and operational concerns associated with aircraft towing are identified, and the benefits and costs of implementing aircraft towing at 20 major US airports are analyzed. It was concluded that extended aircraft towing is technically feasible and that substantial reductions in aircraft fuel consumption and air pollutant emissions can be achieved through its implementation. It was also concluded that, although capital and operating costs associated with towing would be increased, net savings could generally be attained at these airports. Because of the lack of past experience and the necessity of proving the cost effectiveness of the towing concept, a demonstration of the feasibility of large-scale aircraft towing is necessary. The study evaluates the suitability of the 20 study airports as potential demonstration sites and makes recommendations for the first demonstration project.

  9. Summer oxygen depletion in a diked New England estuary

    USGS Publications Warehouse

    Portnoy, J.W.

    1991-01-01

    The diked and freshened Herring River estuary (Wellfleet, Massachusetts) experiences regular summer hypoxia and one- to three-week periods of main stream anoxia, often accompanied by fish kills. Stream hypoxia results from the temperature-dependent increase in oxygen demand of organic matter released by diked salt marsh deposits; periods of total anoxia are induced by heavy rains which increase the runoff of wetland organic matter. Historic reductions in tidal flushing have extended the low salinity region of the estuary normally characterized by high organic loads and minimal flushing. Recurrent main stream anoxia has depressed both migratory and resident aquatic fauna.

  10. Impacts of pesticides in a Central California estuary.

    PubMed

    Anderson, Brian; Phillips, Bryn; Hunt, John; Siegler, Katie; Voorhees, Jennifer; Smalling, Kelly; Kuivila, Kathy; Hamilton, Mary; Ranasinghe, J Ananda; Tjeerdema, Ron

    2014-03-01

    Recent and past studies have documented the prevalence of pyrethroid and organophosphate pesticides in urban and agricultural watersheds in California. While toxic concentrations of these pesticides have been found in freshwater systems, there has been little research into their impacts in marine receiving waters. Our study investigated pesticide impacts in the Santa Maria River estuary, which provides critical habitat to numerous aquatic, terrestrial, and avian species on the central California coast. Runoff from irrigated agriculture constitutes a significant portion of Santa Maria River flow during most of the year, and a number of studies have documented pesticide occurrence and biological impacts in this watershed. Our study extended into the Santa Maria watershed coastal zone and measured pesticide concentrations throughout the estuary, including the water column and sediments. Biological effects were measured at the organism and community levels. Results of this study suggest the Santa Maria River estuary is impacted by current-use pesticides. The majority of water samples were highly toxic to invertebrates (Ceriodaphnia dubia and Hyalella azteca), and chemistry evidence suggests toxicity was associated with the organophosphate pesticide chlorpyrifos, pyrethroid pesticides, or mixtures of both classes of pesticides. A high percentage of sediment samples were also toxic in this estuary, and sediment toxicity occurred when mixtures of chlorpyrifos and pyrethroid pesticides exceeded established toxicity thresholds. Based on a Relative Benthic Index, Santa Maria estuary stations where benthic macroinvertebrate communities were assessed were degraded. Impacts in the Santa Maria River estuary were likely due to the proximity of this system to Orcutt Creek, the tributary which accounts for most of the flow to the lower Santa Maria River. Water and sediment samples from Orcutt Creek were highly toxic to invertebrates due to mixtures of the same pesticides measured in the estuary. This study suggests that the same pyrethroid and organophosphate pesticides that have been shown to cause water and sediment toxicity in urban and agriculture water bodies throughout California, have the potential to affect estuarine habitats. The results establish baseline data in the Santa Maria River estuary to allow evaluation of ecosystem improvement as management initiatives to reduce pesticide runoff are implemented in this watershed. PMID:24464329

  11. Analytical solution of tidal dynamics in convergent estuaries: A review

    NASA Astrophysics Data System (ADS)

    Cai, Huayang; Savenije, Hubert H. G.; Toffolon, Marco

    2013-04-01

    In this contribution we focus on the tidal wave propagation in convergent estuaries, where the cross-sectional area varies approximately as an exponential function along the estuary axis. This kind of estuarine geometry, which is observed in coastal plain estuaries all over the world, including widely studied tidal estuaries such as the Scheldt in the Netherlands, Thames in the UK, Delaware in the USA, can produce amplification or damping of the tidal wave: if the effect of convergence is stronger than the effect of friction, the wave is amplified; if friction is stronger than convergence, the wave is damped. Since real estuaries can experience amplification and damping in different regions, depending primarily on local depth and convergence, a multiple-reach approach is typically required. It has been recently shown that a fully analytical solution for the one-dimensional tidal hydrodynamics can be obtained by solving a set of four implicit analytical equations, i.e., the damping, the phase lag, the scaling and the celerity equations (Toffolon et al., 2006; Savenije et al., 2008; Cai et al., 2012). Such a solution can be applied locally and represents a valuable tool to describe the tidal dynamics in an affordable yet reliable way. Moreover, it provides a theoretical framework that can be used to compare the different assumptions, like for instance the linearization of the friction term, which are exploited in previously derived analytical solutions. It is found that the main differences between the different approaches lie in: 1) the account of local variability (e.g., the depth), 2) the different approximations of the friction term, 3) the account of asymptotic behaviour. The purpose of this review is hence to summarize common features and main differences among the various analytical solutions and finally enhance our understanding of tidal wave propagation in estuaries. References Cai, H., H. H. G. Savenije, and M. Toffolon (2012), A new analytical framework for assessing the effect of sea-level rise and dredging on tidal damping in estuaries, Journal of Geophysical Research, 117, C09023, doi:10.1029/2012JC008000. Savenije, H. H. G., M. Toffolon, J. Haas, and E. J. M. Veling (2008), Analytical description of tidal dynamics in convergent estuaries, Journal of Geophysical Research, 113(C10), doi:10.1029/2007JC004408. Toffolon, M., G. Vignoli, and M. Tubino (2006), Relevant parameters and finite amplitude effects in estuarine hydrodynamics, Journal of Geophysical Research, 111(C10), doi:10.1029/2005JC003104.

  12. Modeling pesticide fate in a small tidal estuary

    USGS Publications Warehouse

    McCarthy, A.M.; Bales, J.D.; Cope, W.G.; Shea, D.

    2007-01-01

    The exposure analysis modeling system (EXAMS), a pesticide fate model developed by the U.S. Environmental Protection Agency, was modified to model the fate of the herbicides atrazine and metolachlor in a small tidally dominated estuary (Bath Creek) in North Carolina, USA where freshwater inflow accounts for only 3% of the total flow. The modifications simulated the changes that occur during the tidal cycle in the estuary, scenarios that are not possible with the original EXAMS model. Two models were created within EXAMS, a steady-state model and a time-variant tidally driven model. The steady-state model accounted for tidal flushing by simply altering freshwater input to yield an estuary residence time equal to that measured in Bath Creek. The tidal EXAMS model explicitly incorporated tidal flushing by modifying the EXAMS code to allow for temporal changes in estuary physical attributes (e.g., volume). The models were validated with empirical measurements of atrazine and metolachlor concentrations in the estuary shortly after herbicide application in nearby fields and immediately following a rain event. Both models provided excellent agreement with measured concentrations. The steady-state EXAMS model accurately predicted atrazine concentrations in the middle of the estuary over the first 3 days and under-predicted metolachlor by a factor of 2-3. The time-variant, tidally driven EXAMS model accurately predicted the rise and plateau of both herbicides over the 6-day measurement period. We have demonstrated the ability of these modified EXAMS models to be useful in predicting pesticide fate and exposure in small tidal estuaries. This is a significant improvement and expansion of the application of EXAMS, and given the wide use of EXAMS for surface water quality modeling by both researchers and regulators and the ability of EXAMS to interface with terrestrial models (e.g., pesticide root zone model) and bioaccumulation models, we now have an easily-accessible and widely accepted means of modeling chemical fate in estuaries. ?? 2006 Elsevier B.V. All rights reserved.

  13. Micro electric propulsion feasibility

    NASA Technical Reports Server (NTRS)

    Aston, Graeme; Aston, Martha

    1992-01-01

    Miniature, 50 kg class, strategic satellites intended for extended deployment in space require an on-board propulsion capability to perform needed attitude control adjustments and drag compensation maneuvers. Even on such very small spacecraft, these orbit maintenance functions can be significant and result in a substantial propellant mass requirement. Development of advanced propulsion technology could reduce this propellant mass significantly, and thereby maximize the payload capability of these spacecraft. In addition, spacecraft maneuverability could be enhanced and/or multi-year mission lifetimes realized. These benefits cut spacecraft replacement costs, and reduce services needed to maintain the launch vehicles. For SDIO brilliant pebble spacecraft, a miniaturized hydrazine propulsion system provides both boost and divert thrust control. This type of propulsion system is highly integrated and is capable of delivering large thrust levels for short time periods. However, orbit maintenance functions such as drag make-up require only very small velocity corrections. Using the boost and/or divert thrusters for these small corrections exposes this highly integrated propulsion system to continuous on/off cycling and thereby increases the risk of system failure. Furthermore, since drag compensation velocity corrections would be orders of magnitude less than these thrusters were designed to deliver, their effective specific impulse would be expected to be lower when operated at very short pulse lengths. The net result of these effects would be a significant depletion of the on-board hydrazine propellant supply throughout the mission, and a reduced propulsion system reliability, both of which would degrade the interceptors usefulness. In addition to SDIO brilliant pebble spacecraft, comparably small spacecraft can be anticipated for other future strategic defense applications such as surveillance and communication. For such spacecraft, high capability and reliability, minimal detectability and low cost are requirements. All these miniature spacecraft share a common characteristic: because of their on-board electronic equipment they have, by design, solar order 50-100 W. In a relative sense, such spacecraft are power rich when compared to other larger spacecraft. This power rich situation is offset by very tight mass budgets, which make reductions in propellant mass requirements a key issue in meeting overall spacecraft minimum mass goals. In principle, power rich and propellant poor brilliant pebbles class spacecraft can benefit from using high specific impulse electric propulsion to reduce chemical propellant mass requirements. However, at power levels of order 50 W, arcjets cannot be made to function, ion thrusters are too complex and heavy and resistojets have too low a specific impulse. Recognizing these capability limitations in existing electric propulsion technology, the SDIO/IST sponsored the Phase I SBIR Micro Electric Propulsion (MEP) thruster study described in this report. The objective of this study was to examine the feasibility of developing a very simple, low mass and small volume, electric thruster for operation on hydrazine at less than 100 W of input power. The feasibility of developing such a MEP thruster was successfully demonstrated by EPL by the discovery of a novel plasma acceleration process. The sections in this report summarize the approach, test results and major accomplishments of this proof-of-concept program.

  14. Micro electric propulsion feasibility

    NASA Astrophysics Data System (ADS)

    Aston, Graeme; Aston, Martha

    1992-11-01

    Miniature, 50 kg class, strategic satellites intended for extended deployment in space require an on-board propulsion capability to perform needed attitude control adjustments and drag compensation maneuvers. Even on such very small spacecraft, these orbit maintenance functions can be significant and result in a substantial propellant mass requirement. Development of advanced propulsion technology could reduce this propellant mass significantly, and thereby maximize the payload capability of these spacecraft. In addition, spacecraft maneuverability could be enhanced and/or multi-year mission lifetimes realized. These benefits cut spacecraft replacement costs, and reduce services needed to maintain the launch vehicles. For SDIO brilliant pebble spacecraft, a miniaturized hydrazine propulsion system provides both boost and divert thrust control. This type of propulsion system is highly integrated and is capable of delivering large thrust levels for short time periods. However, orbit maintenance functions such as drag make-up require only very small velocity corrections. Using the boost and/or divert thrusters for these small corrections exposes this highly integrated propulsion system to continuous on/off cycling and thereby increases the risk of system failure. Furthermore, since drag compensation velocity corrections would be orders of magnitude less than these thrusters were designed to deliver, their effective specific impulse would be expected to be lower when operated at very short pulse lengths. The net result of these effects would be a significant depletion of the on-board hydrazine propellant supply throughout the mission, and a reduced propulsion system reliability, both of which would degrade the interceptors usefulness. In addition to SDIO brilliant pebble spacecraft, comparably small spacecraft can be anticipated for other future strategic defense applications such as surveillance and communication. For such spacecraft, high capability and reliability, minimal detectability and low cost are requirements. All these miniature spacecraft share a common characteristic: because of their on-board electronic equipment they have, by design, solar order 50-100 W. In a relative sense, such spacecraft are power rich when compared to other larger spacecraft. This power rich situation is offset by very tight mass budgets, which make reductions in propellant mass requirements a key issue in meeting overall spacecraft minimum mass goals. In principle, power rich and propellant poor brilliant pebbles class spacecraft can benefit from using high specific impulse electric propulsion to reduce chemical propellant mass requirements. However, at power levels of order 50 W, arcjets cannot be made to function, ion thrusters are too complex and heavy and resistojets have too low a specific impulse. Recognizing these capability limitations in existing electric propulsion technology, the SDIO/IST sponsored the Phase I SBIR Micro Electric Propulsion (MEP) thruster study described in this report. feasibility of developing a very simple, low mass and small volume, electric thruster for operation on hydrazine at less than 100 W of input power. &The feasibility of developing such a MEP thruster was successfully demonstrated by EPL by the discovery of a novel plasma acceleration process. The sections in this report summarize the approach, test results and major accomplishments of this proof-of-concept program.

  15. Spatial variability of suspended sediment concentration within a tidal marsh in San Francisco Estuary

    NASA Astrophysics Data System (ADS)

    Swanson, K.; Drexler, J. Z.; Schoellhamer, D. H.; Buffington, K.; Takekawa, J.

    2012-12-01

    The sustainability of existing marshes and feasibility of future marsh restoration projects in San Francisco Estuary and elsewhere are threatened by a potential imbalance between accelerating sea-level rise and tidal marsh accretion rates. Marsh accretion is, in large part, dependent upon the availability of suspended sediment supplied from adjacent waterways. As water and sediment move across a marsh plain, suspended sediment settles and is trapped by vegetation near the source, resulting in less suspended-sediment concentration (SSC) and deposition in the interior of the marsh. Measurements of deposition and limited observations of SSC within marshes have confirmed a decrease in sediment supply and accumulation from the marsh edge to the marsh interiors, but the spatial variability of SSC has not been quantified in a manner that allows for comparison to a theoretical sediment transport model. For this study, transects of SSC were collected within a marsh at China Camp State Park in the San Francisco Estuary which demonstrate that a dominant pattern of settling can be quantified and generally matches the exponentially decreasing pattern of SSC predicted by a simple advection-settling model. The observed pattern suggests that sediment settling and marsh flow characteristics are consistent both spatially (between transects) and temporally (between monthly sampling events). However, deviations from the predicted pattern occurred systematically at some locations and are likely related to resuspension of sediment from the marsh surface or small, unmapped creek channels that supply sediment to the marsh. Despite these deviations, our data show this simple 1-D model of advection and settling can be used to generalize within-marsh sediment transport as a function of distance from the nearest sediment source.

  16. Environmental management of a highly impacted, urbanized tropical estuary: rehabilitation and restoration

    NASA Astrophysics Data System (ADS)

    Thorhaug, A.

    1980-03-01

    The principles of the dynamics and interrelationships within the dominant subtropical and tropical Caribbean seagrass community have been studied previously before, during, and after impact. From these and scores of observations of damage and recovery patterns in Thalassia ecosystems, a sense of management recovery strategy has emerged. Artificial restoring of Thalassia testudinum seeds into areas cut off from stock (fruit, seeds) appeared feasible on a large scale after the Turkey Point (Biscayne Bay, Miami, Florida) restoration and test sampling throughout North Biscayne Bay. Two large-scale seeding attempts were made; after 11 months they compared favorably with Turkey Point specimens with regard to growth parameters, despite the turbidity and other persistent pollution. Thus, the possible areas in which Thalassia seed restoration can be used has increased to include estuaries of multiple impact still in various stages of recovery after physical and sewage pollution. This technique should be especially useful to developing nations where important nearshore fisheries nurseries based on Thalassia ecosystems have been heavily damaged and now lie barren. Man's impact on the estuary where seed restoration was attempted includes the following activities: 50% of the bay bottom directly dredged or filled (leaving much unconsolidated sediment); 50 million gallons of domestic waste dumped directly into a low flushing part of the bay for 20 years; seven major causeways transecting the bay, restricting circulation and flushing; two artificial inlets made into navigational channels; freshwater sheet flow drastically changed due to channelization by flood-control canals; urban runoff from a million people entering the bay. Most of the impacts have now abated; however, their long-term effects remain.

  17. Large-scale spatial patterns in estuaries: estuarine macrobenthic communities in the Schelde estuary, NW Europe

    NASA Astrophysics Data System (ADS)

    Ysebaert, T.; Herman, P. M. J.; Meire, P.; Craeymeersch, J.; Verbeek, H.; Heip, C. H. R.

    2003-05-01

    Few macrobenthic studies have dealt simultaneously with the two major gradients in estuarine benthic habitats: the salinity gradient along the estuary (longitudinal) and the gradients from high intertidal to deep subtidal sites (vertical gradient). In this broad-scale study, a large data set (3112 samples) of the Schelde estuary allowed a thorough analysis of these gradients, and to relate macrobenthic species distributions and community structure to salinity, depth, current velocities and sediment characteristics. Univariate analyses clearly revealed distinct gradients in diversity, abundance, and biomass along the vertical and longitudinal gradients. In general, highest diversity and biomass were observed in the intertidal, polyhaline zone and decreased with decreasing salinity. Abundance did not show clear trends and varied between spring and autumn. In all regions, very low values for all measures were observed in the subtidal depth strata. Abundance in all regions was dominated by both surface deposit feeders and sub-surface deposit feeders. In contrast, the biomass of the different feeding guilds showed clear gradients in the intertidal zone. Suspension feeders dominated in the polyhaline zone and showed a significant decrease with decreasing salinity. Surface deposit feeders and sub-surface deposit feeders showed significantly higher biomass values in the polyhaline zone as compared with the mesohaline zone. Omnivores showed an opposite trend. Multivariate analyses showed a strong relationship between the macrobenthic assemblages and the predominant environmental gradients in the Schelde estuary. The most important environmental factor was depth, which reflected also the hydrodynamic conditions (current velocities). A second gradient was related to salinity and confirms the observations from the univariate analyses. Additionally, sediment characteristics (mud content) explained a significant part of the macrobenthic community structure not yet explained by the two other main gradients. The different assemblages are further described in terms of indicator species and abiotic characteristics. The results showed that at a large, estuarine scale a considerable fraction of the variation in abundance and biomass of the benthic macrofauna correlated very well with environmental factors (depth, salinity, tidal current velocity, sediment composition).

  18. Abandoned Channel Fill Sequences in Tidal Estuaries

    NASA Astrophysics Data System (ADS)

    Gray, A. B.; Pasternack, G. B.; Goni, M. A.; Watson, E. B.

    2014-12-01

    This study proposes a modification of the current model for abandoned channel fill stratigraphy produced in unidirectional flow river reaches to incorporate seasonal tidal deposition. Evidence supporting this concept came from a study of two consecutive channel abandonment sequences in Ropers Slough of the lower Eel River Estuary in northern California. Aerial photographs showed that Ropers Slough was abandoned around 1943, reoccupied after the 1964 flood, and abandoned again in 1974 with fill continuing to the present. Planform geomorphic characteristics derived from these images were used in conjunction with sub-cm resolution stratigraphic analyses to describe the depositional environment processes and their resultant sedimentary deposits. Results showed that both abandonment sequences recorded quasi-annual scale fluvial/tidal deposition couplets. In both cases tidal deposits contained very little sand, and were higher in organic and inorganic carbon content than the sandier fluvial through-flow deposits. However, the two abandonment fills differed significantly in terms of the temporal progression of channel narrowing and fluvial sediment deposition characteristics. The first abandonment sequence led to a more rapid narrowing of Ropers Slough and produced deposits with a positive relationship between grain size/deposit thickness and discharge. The second abandonment resulted in a much slower narrowing of Ropers Slough and generally thinner fluvial deposits with no clear relationship between grain size/deposit thickness and discharge. The ?13C values and organic nitrogen to organic carbon ratios of deposits from the first phase overlapped with Eel River suspended sediment characteristics found for low flows (1-5 times mean discharge), while those of the second phase were consistent suspended sediment from higher flows (7-10 times mean discharge). The abandoned channel fill sequences appeared to differ due to the topographic steering of bed sediment transport and deposition previously identified in rivers experiencing only unidirectional flow, while also expressing the seasonal dichotomy of fluvial and tidal deposits.

  19. The chemistry of trace elements in estuaries

    SciTech Connect

    Yan, L.

    1990-01-01

    Estuarine mixing processes can be generally divided into two stages. In the low-salinity region (<1%), dissolved Fe and organic carbon are likely released from suspended particles. The release of Fe and organic carbon is caused by deflocculation of colloidal aggregates, which differs from the processes operating in the high salinity region. In the high-salinity region, dissolved Al and Fe are generally removed due to flocculation of Fe-colloids. The behavior of other metals such as Cu, Mn, Ni and Zn varies and seems to be controlled by variable factors. Dissolved {sup 226}Ra is removed through adsorption by resuspended particles, and added through desorption from riverine suspended particles and input from the pore water. This is shown by the data collected from the Mullica River estuary. Equilibrium-speciation calculation for estuarine water predict that Al and Cu are complexed largely with organic ligands. The extent of Ni complexes with organic ligands in estuarine water depends largely on the concentration of organic ligands. Dissolved Mn and Zn do not form significant fraction of metal-organic complexes. Complexing of Fe with organics can delay precipitation of Fe-hydroxides in the course of estuarine mixing. Metal concentrations in estuarine sediments of the Mullica River are primarily controlled by physical processes. The dominant processes are resuspension and sedimentation for suspended sediments, and longitudinal mixing for bottom sediments. In suspended particles, Fe, Mn, and Zn are largely associated with amorphous material, which is clearly in contrast to those for bottom sediments in which most metals are associated with clay minerals. The coastal waters of New Jersey receive considerable Cu, Ni Mn and Zn from anthropogenic sources, and these metals are largely added in the high salinity region.

  20. Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Ebberts, Blaine D.; Tortorici, Cathy; Yerxa, Tracey; Leary, J.; Skalski, John R.

    2008-02-05

    The purpose ofthis document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision-making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows. 1. Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. 2. Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. 3. Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. 4. Maintain the food web to benefit salmonid performance. 5. Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. In conclusion, the estuary RME effort is designed to meet the research and monitoring needs of the estuary Program using an adaptive management process. Estuary RME's success and usefulness will depend on the actual conduct of adaptive management, as embodied in the objectives, implrementation, data, reporting, and synthesis, evaluation, and decision-making described herein.

  1. Predicting fish community properties within estuaries: Influence of habitat type and other environmental features

    NASA Astrophysics Data System (ADS)

    França, Susana; Vasconcelos, Rita P.; Fonseca, Vanessa F.; Tanner, Susanne E.; Reis-Santos, Patrick; Costa, Maria José; Cabral, Henrique N.

    2012-07-01

    Statistical models predicting species distributions are essential not only to increase knowledge on species but for their application in conservation and ecologically-based management. The variation of fish species richness and abundance in the most representative habitats (saltmarsh, mudflat and subtidal) in five estuaries along the Portuguese coast was analysed through seasonal sampling surveys in 2009. Generalized additive models (GAM) were developed to describe the variation of species richness and abundances with a set of geomorphologic, hydrologic and environmental characteristics from the sampled estuaries and habitats. GAM were chosen as the complex interactions dominating these ecosystems and species distribution are non-linear. Final models built for each estuary and for all estuaries together performed well during the calibration phase and also during the validation phase, where an unused data sub-set from each estuary was used. There was not a similar combination of variables retained by the models for the studied estuaries but factors such as the area of the habitat, the distance to estuary mouth, percentage of mud in the sediment and depth were commonly retained. The partial effect of these predictor variables on the variation of species richness and abundance in the estuaries varied markedly and the importance of preserving the heterogeneity of habitats within estuaries was highlighted. Models for each individual estuary performed better than models for estuaries combined. Predictive models could be useful as a preliminary tool to prepare long-term conservation plans at different scales.

  2. The chemical oceanographic consequences of environmental restoration projects in the Golden Horn estuary (Marmara Sea, Turkey).

    PubMed

    Balkis, N; Mfto?lu, E; Aksu, A; Sur, H I; Apak, R

    2010-05-01

    The input of industrial and domestic waste to the horizontal circulation in the Golden Horn Estuary of Marmara Sea has resulted in one of the most polluted estuaries in the past. Consequently, the dissolved oxygen concentrations in both the surface and bottom waters decreased toward to the estuary head during 1998-2005. In contrast, the total suspended solids content of the surface water decreased toward to the estuary mouth. However, construction of the operational collector system surrounding the estuary during the process of rehabilitation projects, combined with the opening of the middle pontoons of the Valide Sultan Bridge, resulted in gradually improved water quality of the estuary with a concomitant decrease in pollution. However, phytoplankton blooms and eutrophication persist especially in the innermost part of the Golden Horn in 2005. The region from the estuary mouth up to Camialti has a dynamic structure, and sufficient circulation seemingly occurs in this part of the Golden Horn. PMID:19353286

  3. Biomonitoring heavy metals in estuaries: a field comparison of two brown algae species inhabiting upper estuarine reaches.

    PubMed

    Barreiro, Rodolfo; Picado, Laura; Real, Carlos

    2002-04-01

    Biomonitoring dissolved heavy metals within estuaries, particularly at their upper reaches, frequently has to rely on several biomonitors; rarely a single species thrives all along the salinity gradient. To properly do so, it must be established whether those biomonitors actually accumulate heavy metals alike. In this study, two brown seaweeds from the upper section of three NW Spain estuaries--the widely-known Fucus vesiculosus and the estuarine Fucus ceranoides--were compared as metal biomonitors. Both species were collected at five locations where they either coexist or live close to each other and their heavy metal content (Cu, Cr, Mn, Zn, Fe, Al) was measured. Analyses were appropriately replicated for each species x location combination to allow a statistically reliable detection of differences in bioaccumulation, with particular emphasis on the magnitude of interspecific differences. The lack of significant differences for Cu, Mn, and Zn contents in F. ceranoides and F. vesiculosus supports the feasibility of their joint use to monitor these metals along the estuaries. Conversely, F. ceranoides concentrated significantly higher levels of Cr, Fe, and Al than F. vesiculosus and hence combining data for both fucoids to monitor these elements seems impractical. The correlation of species differences together with a similar Al:Fe ratio in both weed tissue and sediment suggest that Cr, Fe, and Al tissue-burdens might be considerably biased by sediment retained on the surface of the weed. Parallel analyses of Al and/or Fe in seaweeds and sediments could serve to keep track of this interference and may help to combine data from both fucoids for monitoring elements like Cr. PMID:12002281

  4. Multnomah County Hydrokinetic Feasibility Study: Final Feasibility Study Report

    SciTech Connect

    Stephen Spain

    2012-03-15

    HDR has completed a study of the technical, regulatory, and economic feasibility of installing hydrokinetic turbines under the Morrison, Broadway, and Sellwood bridges. The primary objective of installing hydrokinetic turbines is a demonstration of in-stream hydrokinetic technologies for public education and outreach. Due to the low gradient of the Lower Willamette and the effects of the tide, velocities in the area in consideration are simply not high enough to economically support a commercial installation. While the velocities in the river may at times provide enough energy for a commercial turbine to reach capacity, the frequency and duration of high flow events which provide suitable velocities is not sufficient to support a commercial hydrokinetic installation. We have observed that over an 11 year period, daily average velocities in the Lower Willamette exceeded a nominal cut-in speed of 0.75 m/s only 20% of the time, leaving net zero power production for the remaining 80% of days. The Sellwood Bridge site was estimated to have the best hydrokinetic resource, with an estimated average annual production of about 9,000 kWh. The estimated production could range from 2,500 kWh to 15,000 kWh. Based on these energy estimates, the amount of revenue generated through either a power purchase agreement (PPA) or recovered through net metering is not sufficient to repay the project costs within the life of the turbine. The hydrokinetic resource at the Morrison and Broadway Bridges is slightly smaller than at the Sellwood Bridge. While the Broadway and Morrison Bridges have existing infrastructure that could be utilized, the project is not expected to generate enough revenue to repay the investment. Despite low velocities and energy production, the sites themselves are favorable for installation of a demonstration or experimental project. With high public interest in renewable energy, the possibility exists to develop a hydrokinetic test site which could provide developers and scientists a location to temporarily deploy and test hydrokinetic devices, and also function as an educational tool for the general public. Bridge piers provide an excellent pre-existing anchor point for hydrokinetic devices, and existing infrastructure at the Morrison and Broadway Bridges may reduce installation costs. Opportunity exists to partner with local universities with engineering and environmental interest in renewable energy. A partnership with Portland State University’s engineering school could provide students with an opportunity to learn about hydrokinetics through senior design projects. Oregon State University and University of Washington, which are partnered through the Northwest National Marine Renewable Energy Center (NNMREC) to study and test hydrokinetic technology, are also relatively local to the site. In addition to providing an opportunity for both public and private entities to learn technically about in-stream kinetics, this approach will encourage grant funding for outreach, education, and product development, while also serving as a positive community relations opportunity for the County and its partners.

  5. APPENDIX C - ADDITIONAL INFORMATION ON FLUSHING IN ESTUARIES

    EPA Science Inventory

    Water residence time is an important determinant of the sensitivity of the response of estuaries and other water bodies to nutrient loading. A variety of terms such as residence time, flushing time, transit time, turnover time, and age are used to describe time scales for transpo...

  6. Forward for book entitled "Estuaries: Classification, Ecology, and Human Impacts"

    EPA Science Inventory

    The author was introduced to the science of estuaries as a graduate student in the early 1980s, studying the ecology of oyster populations in Chesapeake Bay. To undertake this research, he needed to learn not only about oyster biology, but also about the unique physical and chemi...

  7. NEW YORK HARBOR ESTUARY PROGRAM: TOXICS MONITORING MODELING

    EPA Science Inventory

    This activity has resulted in the completion of a toxics model for the New York-New Jersey Harbor Estuary that is now being used for developing TMDLs for the Harbor. Chemicals of concern center on metals, PCBs, Dioxin, PAHs and Pesticides.

  8. STATISTICAL SUMMARY EMAP-ESTUARIES VIRGINIAN PROVINCE - 1991

    EPA Science Inventory

    Annual monitoring of indicators of the ecological condition of bays and estuaries within the Virginian Province (Cape Cod, MA to Cape Henry, VA) was conducted by the U.S. EPA's Environmental Monitoring and Assessment Program (EMAP) during July, August, and September, 1991. ata we...

  9. Invasion by stages in the St Louis River estuary

    EPA Science Inventory

    The St. Louis River estuary is recognized as an invasive species hotspot - the harbor ranks among the top locations in the Great Lakes reporting the first occurrence of new, aquatic non-native species. To date, 18 non-native benthic invertebrate, 4 non-native crusta...

  10. Reference Condition Approach for Numeric Nutrient Criteria for Oregon Estuaries

    EPA Science Inventory

    Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

  11. ECOLOGICAL CONDITION OF ESTUARIES IN THE GULF OF MEXICO

    EPA Science Inventory

    The Gulf of Mexico is a vast natural resource that encompasses the coastal areas of western Florida, Alabama, Mississippi, Louisiana and Texas, as well as a portion of Mexico. Many estuaries flow into the Gulf of Mexico and serve as nursery grounds for fish, habitat for a wide va...

  12. Do Sturgeon limit burrowing shrimp populations in Pacific Northwest estuaries?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Green sturgeon (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) are common seasonal inhabitants of coastal estuaries from California USA to British Columbia, Canada. Both species are anadromous spending significant portions of their lives at sea and in their natal streams, but t...

  13. Man's Impact on the Environment: The Estuary as an Ecosystem.

    ERIC Educational Resources Information Center

    Brevard County School Board, Cocoa, FL.

    This environmental education guide focuses on man's impact on the estuary. The program contained in the guide is developed around the following nine questions: (1) What is a definition of the ecosystem being investigated?; (2) What are some of the biotic and abiotic features of the ecosystem and how do these features interrelate?; (3) Where are

  14. Ecohydrology of Greenhouse Gas Fluxes in a Temperate Estuary

    NASA Astrophysics Data System (ADS)

    Vargas, R.; Michael, H. A.; Sanchez, Z.; Seyfferth, A.

    2014-12-01

    Estuaries are among the world's most biologically rich and economically important ecosystems, and are vulnerable as they are threatened by the front lines of natural and human-induced change. It is unclear which are the biophysical processes that control carbon dynamics (including CO2 and CH4) in estuaries, and whether these ecosystems are net sources or sinks of carbon to the atmosphere. Most efforts have been placed to study CO2 dynamics, but the complex biogeochemical reactions within the sediments that play a role of in situ GHG production cannot be forgotten, especially for CH4 dynamics in wetlands. We present results of ecosystem-scale CO2, CH4 and H2O fluxes using the eddy covariance technique in a brackish temperate estuary near the Delaware Bay, USA. We also present a synthesis effort to bring together concepts and measurements form hydrology and biogeochemistry to explain the temporal patterns and magnitudes of the GHG fluxes measured by the eddy covariance technique. We conclude that an ecohydrological approach and a deeper understanding of biogeochemical characteristics and reactions within the sediments is needed to better understand GHG fluxes in estuaries.

  15. BENTHIC NUTRIENT FLUX IN A SMALL ESTUARY IN NORTHWESTERNFLORIDA (USA)

    EPA Science Inventory

    Benthic Nutrient Flux in a Small Estuary in Northwestern Florida(USA).Gulf and Caribbean Research 18, 15-25, 2006.

    Benthic nutrient fluxes of ammonium (NH4+), nitrite/nitrate (NO2-+NO3-), phosphate (PO4-), and dissolved silica (DSi) were measured in Escambia Bay, an estuar...

  16. Invasion by stages in the St Louis River estuary

    EPA Science Inventory

    The St. Louis River estuary is recognized as an invasive species “hotspot” - the harbor ranks among the top locations in the Great Lakes reporting the first occurrence of new, aquatic non-native species. To date, 18 non-native benthic invertebrate, 4 non-native crusta...

  17. Larval fish distribution in the St. Louis River estuary

    EPA Science Inventory

    Our objective was to determine what study design, environmental, and habitat variables contribute to the distribution and abundance of larval fish in the St. Louis River estuary. Larval fish habitat associations are poorly understood in Great Lakes coastal wetlands, yet critical ...

  18. PEAK STREAMFLOW - VIRGINIA PORTION OF THE ALBEMARLE-PAMLICO ESTUARY

    EPA Science Inventory

    Peak discharge data from the U.S. Geological Survey (http://waterdata.usgs.gov/nwis-w/VA) for gaging stations within the Virginia portion of the Albemarle-Pamlico Estuary watershed. Record dates vary by gaging station. Data for each station are located in a text file named by sta...

  19. DAILY STREAMFLOW - VIRGINIA PORTION OF THE ALBEMARLE-PAMLICO ESTUARY

    EPA Science Inventory

    Daily mean discharge data from the U.S. Geological Survey (http://waterdata.usgs.gov/nwis-w/VA) for gaging stations within the Virginia portion of the Albemarle-Pamlico Estuary watershed. Record dates vary by gaging station. Data for each station are located in a text file named ...

  20. ASSESSING THE ECOLOGICAL CONDITION OF VERACRUZ, MEXICO ESTUARIES

    EPA Science Inventory

    Macauley, John, Hector A. Vasquez, George Craven and P. Thomas Heitmuller. In press. Assessing the Ecological Condition of Veracruz, Mexico Estuaries (Abstract). To be presented at the EPA Science Forum: Healthy Communities and Ecosystems, 1-3 June 2004, Washington, DC. 1 p. (ERL...

  1. ASSESSING THE ECOLOGICAL CONDITION OF VERACRUZ, MX ESTUARIES

    EPA Science Inventory

    As part of an international technology transfer activity between EPA's Office of Research and Development and the state of Veracruz's Sub-secretary of the Environment, 50 stations within estuaries along the gulf coast of the state of Veracruz MX, were sampled during June and July...

  2. Revised predictive equations for salt intrusion modelling in estuaries

    NASA Astrophysics Data System (ADS)

    Gisen, J. I. A.; Savenije, H. H. G.; Nijzink, R. C.

    2015-01-01

    For one-dimensional salt intrusion models to be predictive, we need predictive equations to link model parameters to observable hydraulic and geometric variables. The one-dimensional model of Savenije (1993b) made use of predictive equation for the Van der Burgh coefficient K and the dispersion at the seaward boundary D0. Here we have improved these equations by using an expanded database, including new previously un-surveyed estuaries. Furthermore, we derived a revised predictive equation for the dispersion at tidal average (TA) condition and with the boundary situated at the well identifiable inflection point where the estuary changes from wave-dominated to tide-dominated geometry. We used 89 salinity profiles in 30 estuaries (including 7 recently studied estuaries in Malaysia), and empirically derived a range of equations using various combinations of dimensionless parameters. We split our data in two separated datasets: (1) with more reliable data for calibration, and (2) with less reliable data for validation. The dimensionless parameters that gave the best performance depended on the geometry, tidal strength, friction and the Richardson Number. The limitation of the equations is that the friction is generally unknown. In order to overcome this problem, a coupling has been made with the analytical hydraulic model of Cai et al. (2012), which makes use of observed tidal damping and by which the friction can be determined.

  3. Estuarine habitat utilization by birds in Yaquina Estuary, Oregon

    EPA Science Inventory

    A wide variety of bird species are highly dependent on intertidal wetland habitats. Because of this dependency, birds are viewed as important indicators of wetland structure and function. Wetlands in Yaquina Bay along with the tidal wetlands in other Pacific coastal estuaries r...

  4. ANIMAL-HABITAT ASSOCIATIONS IN PACIFIC NORTHWEST ESTUARIES

    EPA Science Inventory

    The mission of the Pacific Coastal Ecology Branch (EPA, Newport, OR) is to determine the effects of habitat alteration by stressors on ecological resources in Pacific Northwest (PNW) estuaries. Research being conducted in support of this mission includes identifying critical hab...

  5. Phenology of larval fish in the St. Louis River estuary

    EPA Science Inventory

    Little work has been done on the phenology of fish larvae in Great Lakes coastal wetlands. As part of an aquatic invasive species early detection study, we conducted larval fish surveys in the St. Louis River estuary (SLRE) in 2012 and 2013. Using multiple gears in a spatially ba...

  6. ACROCHEMICAL AND NUTRIENT IMPACTS ON ESTUARIES AND OTHER AQUATIC SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper summarizes the Agrochemical and Nutrient Impacts on Estuaries Symposium held at the 220th American Chemical Society National Meeting. The focus of the symposium was to highlight on-going research efforts to understand estuarine function and pollutant fate in these important ecosystems. E...

  7. Revised predictive equations for salt intrusion modelling in estuaries

    NASA Astrophysics Data System (ADS)

    Gisen, J. I. A.; Savenije, H. H. G.; Nijzink, R. C.

    2015-06-01

    For one-dimensional salt intrusion models to be predictive, we need predictive equations to link model parameters to observable hydraulic and geometric variables. The one-dimensional model of Savenije (1993b) made use of predictive equations for the Van der Burgh coefficient K and the dispersion at the seaward boundary D0. Here we have improved these equations by using an expanded database, including new previously un-surveyed estuaries. Furthermore, we derived a revised predictive equation for the dispersion at tidal average condition and with the boundary situated at the well identifiable inflection point where the estuary changes from wave-dominated to tide-dominated geometry. We used 89 salinity profiles in 30 estuaries (including seven recently studied estuaries in Malaysia), and empirically derived a range of equations using various combinations of dimensionless parameters. We split our data in two separated data sets: (1) with more reliable data for calibration, and (2) with less reliable data for validation. The dimensionless parameters that gave the best performance depended on the geometry, tidal strength, friction and the Richardson number. The limitation of the equations is that the friction is generally unknown. In order to overcome this problem, a coupling has been made with the analytical hydraulic model of Cai et al. (2012), which makes use of observed tidal damping and by which the friction can be determined.

  8. Plutonium isotope ratios in the Yenisey and Ob estuaries.

    PubMed

    Skipperud, L; Oughton, D H; Fifield, L K; Lind, O C; Tims, S; Brown, J; Sickel, M

    2004-01-01

    Over the past 50 years, nuclear weapons' tests and releases from the nuclear industry have introduced anthropogenic plutonium into the environment. In the Arctic environment, the main source of plutonium is from the atmospheric weapons testing, but previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases can give rise to enhanced local concentrations. The present paper presents results from determination of plutonium concentrations and isotope ratios in the sediment samples collected during various expeditions to the Kara Sea, the Ob and Yenisey estuaries and their river systems. The data indicated a clear influence from a low 240Pu:239Pu source in surface sediments collected from the Yenisey estuary, whereas plutonium in Ob estuary sediments is dominated by global fallout. The results also show an increase in plutonium concentration (from 0.003 to 11Bq/kg) and a decrease in 240Pu:239Pu isotope ratio (from 0.16 to 0.05) going upstream from the Yenisey estuary towards the nuclear installation at Krashnoyarsk. PMID:14987709

  9. SUSCEPTIBILITY OF A NORTHEASTERN GULF OF MEXICO ESTUARY TO HYPOXIA

    EPA Science Inventory

    Bottom water hypoxia is a common adverse consequence of nutrient enrichment in estuaries and coastal waters. To protect against hypoxia, it is helpful to know which waters are most susceptible to hypoxia. Hypoxia has been observed regularly in Pensacola Bay, a northeastern Gulf o...

  10. The tidal asymmetries and residual flows in Ems Estuary

    NASA Astrophysics Data System (ADS)

    Pein, Johannes Ulrich; Stanev, Emil Vassilev; Zhang, Yinglong Joseph

    2014-12-01

    A 3D unstructured-grid numerical model of the Ems Estuary is presented. The simulated hydrodynamics are compared against tidal gauge data and observations from research cruises. A comparison with an idealized test reveals the capability of the model to reproduce the secondary circulation patterns known from theoretical results. The simulations prove to be accurate and realistic, confirming and extending findings from earlier observations and modeling studies. The basic characteristics of dominant physical processes in the estuary such as tidal amplification, tidal damping, overtide generation, baroclinicity and internal mixing asymmetry are quantified. The model demonstrates an overall dominance of the flood currents in most of the studied area. However, the hypsometric control in the vicinity of Dollart Bay reverses this asymmetry, with the ebb currents stronger than the flood ones. Small-scale bathymetric characteristics and baroclinicity result in a very complex interplay between dominant physical mechanisms in different parts of the tidal channels and over the tidal flats. Residual flow reveals a clear overturning circulation in some parts of the estuary which is related to a mixing asymmetry between flood and ebb currents. We demonstrate that while areas close to the tidal river exhibit overall similarity with density controlled estuarine conditions, in large areas of the outer estuary barotropic forcing and complex bathymetry together with the density distribution affect substantially the horizontal circulation.

  11. ECOLOGICAL CONDITION OF THE ESTUARIES OF OREGON AND WASHINGTON

    EPA Science Inventory

    Estuaries are bodies of water that receive freshwater and sediment from rivers and saltwater from the oceans. They are transition zones between the fresh water of a river and the salty environment of the sea. This interaction produces a unique environment that supports wildlife...

  12. MORRO BAY NATIONAL ESTUARY PROGRAM, FIRST IR 2002

    EPA Science Inventory

    The Morro Bay National Estuary Program is a "Tier V program and is, therefore, required to submit a "full review" of its CCMP implementation progress and overall status of the program in 2002. The MBNEP1s Local Policy Committee completed and approved the CCMP in mid-2001; the CCM...

  13. MOBILE BAY NATIONAL ESTUARY PROGRAM IMPLEMENTATION REVIEW 2002

    EPA Science Inventory

    The Mobile Bay National Estuary Program's Comprehensive Conservation and Management Plan was finalized on April 22, 2002. The guidance document for the preparation of this Implementation Review states "EPA, in recognition that each NEP may have different areas of emphasis, streng...

  14. LATITUDINAL GRADIENTS IN BENTHIC COMMUNITY COMPOSITION IN WESTERN ATLANTIC ESTUARIES

    EPA Science Inventory

    The community structure of benthic macroinvertebrates from estuaries along the Atlantic coast of North America from Cape Cod, MA, to Biscayne Bay, FL, were compared. Benthic data were collected over a 5 year period (1990 to 1995) by the U.S. Environmental Protection Agency's Envi...

  15. [Research the biogeochemical processes of nutrients in Minjiang Estuary].

    PubMed

    Ye, Xiang; Chen, Jian; Ji, Wei-Dong; Li, Dong-Yi

    2011-02-01

    The variations in the concentration and distribution of nutrients and influencing factors in the Minjiang Estuary with a tidal cycle were investigated based on the data obtained during field observations in May 2007. The results showed the suspended sediment, dissolved inorganic nitrogen and silicate were opposite to the change of tidal, while the water level and salinity were consistent with tidal. The buffer mechanism of phosphate was controlled by suspended sand and water. The concentrations of silicate, phosphate and inorganic nitrogen were ranged 0.63-9.00 mg/L, 0.013-0.075 mg/L, 0.33-4.24 mg/L respectively. The contents of dissolved inorganic nitrogen in water mass increased remarkably comparing 1980s because of agriculture, industry and living. The research indicated that the nitrate and silicate were conservative, but phosphate was non-conservative in the biogeochemical processes of nutrients in Minjiang Estuary. The diluted water carried abundant inorganic nitrogen, silicate nutrients to Minjiang Estuary and thus phosphate was similar between diluted water and sea water. Based on the results of nutrient ratios, it was suggested that phosphate was a limiting factor for phytoplankton growth in the Minjiang Estuary. PMID:21528557

  16. FIELD SAMPLING IN ESTUARIES: THE RELATIONSHIP OF SCALE TO VARIABILITY

    EPA Science Inventory

    The spatial/temporal scaling problem (i.e., fitting a given research question to the dimensions of variability of the study area) is particularly pronounced in highly variable systems such as estuaries. Long-term, multidisciplinary studies in the Apalachicola Bay system were used...

  17. Environmental features and macrofauna of Kahana Estuary, Oahu, Hawaii

    USGS Publications Warehouse

    Maciolek, J.A.; Timbol, A.S.

    1981-01-01

    Lack of ecological information on Hawaiian estuaries prompted an intensive 2-year study of a small (5.7 ha) stream-mouth estuary on windward Oahu. Water quality and macrofauna were sampled weekly at seven stations. The water mass was strongly stratified vertically except during freshets. Average values for water column temperature and bottom salinity were 23.2°C and 12‰ at the head to 28.3°C and 28‰ at the mouth. Dissolved oxygen saturation in the water column varied from about 50% at night to 140% in the afternoon. Usually, bottom waters were 3–6°C warmer than surface waters and sometimes showed severe oxygen depletion.Macrofauna, collected primarily by seining, consisted mainly of decapod crustaceans (four species of crabs, seven species of shrimps) and fishes (24 species). Other typical estuarine taxons (mollusks, barnacles, polychaetes) were scarce or absent. Diversity increased seaward from 14 species near the estuary head to 29 species near the mouth. Three species of crustaceans and six of fishes were captured at all stations. Most abundant were the native prawn, Macrobrachium grandimanus, and mullet, Mugil cephalus. Perennially resident adults occurred among crustaceans and gobioid fishes; most other fishes were present as juveniles and sporadic adults. Comparisons with other data suggest that more than 50 species of native fishes may occur in Hawaiian estuaries, and that estuarine macrofaunal diversity on oceanic islands is much lower than on continents at similar latitudes.

  18. SAN JUAN BAY ESTUARY, COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN

    EPA Science Inventory

    This Comprehensive Conservation and Management Plan (CCMP) contains information about the overall health of the San Juan Bay Estuary (SJBE) as well as proposed solutions to identified problems. These solutions, or Action Plans, are the result of a more than 4-year process of cons...

  19. COASTAL BEND BAYS & ESTUARIES PROGRAM IMPLEMENTATION REVIEW 2004

    EPA Science Inventory

    The Coastal Bend Bays & Estuaries Program, Inc. (CBBEP) is a nonprofit 501(c)(3)organization. The CBBEP project area encompasses 12 counties coincident with the Coastal Bend Council of Governments and extends from the Land-Cut in the Laguna Madre, through the Corpus Christi Bay s...

  20. SARASOTA BAY NATIONAL ESTUARY PROGRAM, A FRAMEWORK FOR ACTION

    EPA Science Inventory

    Sarasota Bay: Framework for Action was produced by the Sarasota Bay National Estuary Program to characterize the condition of Sarasota Bay and present preliminary options for Bay improvement. The publication is a precursor to the CCMP. Past destruction of sea grasses and mangrove...

  1. PERSISTENCE OF AROCLOR (TRADE NAME) 1254 IN A CONTAMINATED ESTUARY

    EPA Science Inventory

    The brief report summarizes the concentrations of PCB's in oyster tissue (Crassostrea virginica) observed from April 1969 to June 1976 at three locations in the Escambia Bay estuary, following elimination of an accidental leak of Aroclor 1254 from an industrial site. Data showed ...

  2. Estuaries May Face Increased Parasitism as Sea Levels Rise

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-12-01

    Invertebrates in estuaries could be at a greater risk of parasitism as climate change causes sea levels to rise. A new paper published 8 December in Proceedings of the National Academy of Sciences of the United States of America (doi:10.1073/pnas.1416747111) describes how rapid sea level rise in the Holocene affected the population of parasitic flatworms called trematodes.

  3. Sources and Loading of Nitrogen to U.S. Estuaries

    EPA Science Inventory

    Previous assessments of land-based nitrogen loading and sources to U.S. estuaries have been limited to estimates for larger systems with watersheds at the scale of 8-digit HUCs and larger, in part due to the coarse resolution of available data, including estuarine watershed bound...

  4. Approaches for Development of Nutrient Criteria in Oregon Estuaries

    EPA Science Inventory

    Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

  5. CHEMICAL CARCINOGENS IN BIVALVE MOLLUSKS FROM OREGON ESTUARIES

    EPA Science Inventory

    The research undertaken involved the use of indigenous populatons of bivalve mollusks as monitors for detecting and quantifying environmental benzo(s)pyrene (BAP) in Oregon estuaries. Short-term and long-term studies were conducted in order to establish baseline levels of BAP and...

  6. Tidal variability of lateral advection in a coastal plain estuary

    NASA Astrophysics Data System (ADS)

    Basdurak, N. B.; Valle-Levinson, A.

    2013-07-01

    Tidal variability of lateral advection of momentum (vuy, where u and v are along-estuary and lateral flows, respectively, and the subindex indicates differentiation with respect to the cross-estuary direction) was investigated in a coastal plain estuary with observations at Hampton Roads, which is the transition between the James River and Chesapeake Bay. Towed current velocity profiles and hydrographic profiles were captured during 9 expeditions in 2004 and 2005, to determine the intratidal and spatial changes in lateral advection of momentum and its contribution to along-channel flow. Curvature effects and lateral density gradients were important in driving lateral circulation and in modifying intratidal lateral advection of momentum. Lateral advection had the same order of magnitude as the baroclinic pressure gradient. Its contribution to the along-channel momentum balance was greatest during or just after peak flood and weakest at the end of ebb. During peak flood and peak ebb, the spatial distribution of vuy was seaward at the southern (left) side near surface and at the northern side (right) near bed (looking up-estuary), and landward in the rest of the channel. During slack periods the vuy structures were mostly landward. Observations were in good agreement with analytical model results during peak ebb and flood, but inconsistent during slack periods. The discrepancies between model results and field measurements can be attributed to bathymetry-density gradient interactions, which enhanced ebb-to-flood asymmetries in the along-channel and lateral flow.

  7. BIVALVES AS BIOMONITORS IN THE NEUSE RIVER AND ESTUARY

    EPA Science Inventory

    In eastern North Carolina the Neuse River and Neuse Estuary have been heavily impacted by the byproducts of row crop and livestock agriculture, forestry operations, and industry as well as effluent from municipal wastewater treatment plants. Non-point pollutants derived from thes...

  8. The chemical control of soluble phosphorus in the Amazon estuary

    NASA Technical Reports Server (NTRS)

    Fox, L. E.; Wofsy, S. C.; Sager, S. L.

    1986-01-01

    The role of sediments in controlling concentrations of soluble phosphorous in the Amazon estuary is examined. The efflux of phosphorous through the estuary is calculated using data collected on field excursions in December 1982 and May 1983, and laboratory mixing experiments. It is observed that soluble phosphorus was released from bottom sediments at a rate of 0.2 micro-M/day, when in seawater and deionizd water mixtures. The relation between release rates and salinity and sediment concentrations is studied. A one-dimensional dispersion model was developed to estimate phosphate inputs to the estuary. The model predicted total fluxes of soluble inorganic phosphorous of 15 x 10 to the 6th mole/day for December 1982 and 27 x 10 to the 6th mole/day for May 1983; the predictions correlate with field observations. It is noted that phosphorous removal is between 0 and 4 ppt at a rate of 0.044 + or - 0.01 micron-M/ppt per day and the annual mean input of phophorous from Amazon to outer-estuary is 23 x 10 to the 6th moles/day.

  9. Biogeochemical value of managed realignment, Humber estuary, UK.

    PubMed

    Andrews, J E; Burgess, D; Cave, R R; Coombes, E G; Jickells, T D; Parkes, D J; Turner, R K

    2006-12-01

    We outline a plausible, albeit extreme, managed realignment scenario ('Extended Deep Green' scenario) for a large UK estuary to demonstrate the maximum possible biogeochemical effects and economic outcomes of estuarine management decisions. Our interdisciplinary approach aims to better inform the policy process, by combining biogeochemical and socioeconomic components of managed realignment schemes. Adding 7494 ha of new intertidal area to the UK Humber estuary through managed realignment leads to the annual accumulation of a 1.2 x 10(5) t of 'new' sediment and increases the current annual sink of organic C and N, and particle reactive P in the estuary by 150%, 83% and 50%, respectively. The increase in intertidal area should also increase denitrification. However, this positive outcome is offset by the negative effect of enhanced greenhouse gas emissions in new marshes in the low salinity region of the estuary. Short-term microbial reactions decrease the potential benefits of CO(2) sequestration through gross organic carbon burial by at least 50%. Net carbon storage is thus most effective where oxidation and denitrification reactions are reduced. In the Humber this translates to wet, saline marshes at the seaward end of estuaries. Cost-benefit analysis (CBA) was used to determine the economic efficiency of the Extended Deep Green managed realignment. When compared to a 'Hold-the-Line' future scenario, i.e. the present state/extent of sea defences in the estuary, the CBA shows that managed realignment is cost effective when viewed on >25 year timescales. This is because capital costs are incurred in the first years, whereas the benefits from habitat creation, carbon sequestration and reduced maintenance costs build up over time. Over 50- and 100-year timescales, the Extended Deep Green managed realignment scenario is superior in efficiency terms. The increased sediment accumulation is also likely to enhance storage of contaminant metals. In the case of Cu, a metal that currently causes significant water quality issues, Cu removal due to burial of suspended sediment in realigned areas translates to a value of approximately pounds sterling 1000 a(-1) (avoided clean up costs). Although this is not formally included in the CBA it illustrates another likely positive economic outcome of managed realignment. Although we focus on the Humber, the history of reclamation and its biogeochemistry is common to many estuaries in northern Europe. PMID:16996577

  10. Feasibility of Automated Adaptive GCA (Ground Controlled Approach) Controller Training System.

    ERIC Educational Resources Information Center

    Feuge, Robert L.; And Others

    An analysis of the conceptual feasibility of using automatic speech recognition and understanding technology in the design of an advanced training system was conducted. The analysis specifically explored application to Ground Controlled Approach (GCA) controller training. A systems engineering approach was followed to determine the feasibility of

  11. WERF MACT Feasibility Study Report

    SciTech Connect

    B. Bonnema; D. Moser; J. Riedesel; K. Kooda; K. Liekhus; K. Rebish; S. Poling

    1998-11-01

    This study was undertaken to determine the technical feasibility of upgrading the Waste Experimental Reduction Facility (WERF) at the Idaho National Engineering and Environmental Laboratory to meet the offgas emission limits proposed in the Maximum Achievable Control Technologies (MACT)rule. Four practicable offgas treatment processes were identified, which, if installed, would enable the WERF to meet the anticipated MACT emission limits for dioxins and furans (D/F), hydrochloric acid (HCI), and mercury (Hg). Due to the three-year time restraint for MACT compliance, any technology chosen for the upgrade must be performed within the general plant project funding limit of $5 M. The option selected consists of a partial-quench evaporative cooler with dry sorbent injection for HCI removal followed by a sulfur-impregnated activated carbon bed for Hg control. The planning cost estimate for implementing the option is $4.17 M (with 24% contingency). The total estimated cost includes capital costs, design and construction costs, and project management costs. Capital costs include the purchase of a new offgas evaporative cooler, a dry sorbent injection system with reagent storage, a new fabric filter baghouse, a fixed carbon bed absorber, and two offgas induced draft exhaust fans. It is estimated that 21 months will be required to complete the recommended modification to the WERF. The partial-quench cooler is designed to rapidly cool the offgas exiting the secondary combustion chamber to minimize D/F formation. Dry sorbent injection of an alkali reagent into the offgas is recommended. The alkali reacts with the HCI to form a salt, which is captured with the fly ash in the baghouse. A design HCI removal efficiency of 97.2% allows for the feeding 20 lbs/hr of chlorine to the WERF incinerator. The sorbent feed rate can be adjusted to achieve the desired HCI removal efficiency. A fixed bed of sulfur-impregnated carbon was conservatively sized for a total Hg removal capacity when feeding 10 g/hr Hg to the WERF incinerator. An added benefit for using carbon adsorption is that the activated carbon will also capture a large fraction of any residual D/F present in the offgas.

  12. Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, Annual Report 2009

    SciTech Connect

    Diefenderfer, Heida L.; Johnson, Gary E.; Sather, Nichole K.; Skalski, John R.; Dawley, Earl M.; Coleman, Andre M.

    2010-08-01

    This report describes the 2009 research conducted under the U.S. Army Corps of Engineers (USACE or Corps) project EST-09-P-01, titled “Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary.” The research was conducted by the Pacific Northwest National Laboratory, Marine Science Laboratory and Hydrology Group, in partnership with the University of Washington, School of Aquatic and Fishery Sciences, Columbia Basin Research, and Earl Dawley (NOAA Fisheries, retired). This Columbia River Fish Mitigation Program project, referred to as “Salmonid Benefits,” was started in FY 2009 to evaluate the state-of-the science regarding the ability to quantify the benefits to listed salmonids1 of habitat restoration actions in the lower Columbia River and estuary.

  13. Feasibility of a simplified fuel additive evaluation protocol

    SciTech Connect

    Lister, S.J.; Hunzinger, R.D.; Taghizadeh, A.

    1998-12-31

    This report describes the work carried out during the four stages of the first phase of a project that involved the determination of the feasibility of replacing the Association of American Railroads Recommended Practice (ARRP) 503 protocol for testing diesel fuel oil additives with a new procedure using the single cylinder research engine SCRE-251 as the laboratory test engine, which tests for both engine performance as well as emissions compliance. The report begins with a review of the literature on fuel additive testing, then reviews the new US Environmental Protection Agency regulations regarding locomotive diesel emissions. This is followed by a review of the ARRP 503 protocol and the proposed new procedure, a comparison of the ARRP 503 test engines and the SCRE-251, and a study of the SCRE-251`s ability to represent a multi-cylinder medium-speed diesel engine. Appendices include fuel additive manufacturers` information sheets.

  14. Columbia River Estuary Ecosystem Classification Concept and application

    USGS Publications Warehouse

    Simenstad, Charles A.; Burke, Jennifer L.; O'Connor, Jim E.; Cannon, Charles; Heatwole, Danelle W.; Ramirez, Mary F.; Waite, Ian R.; Counihan, Timothy D.; Jones, Krista L.

    2011-01-01

    This document describes the concept, organization, and application of a hierarchical ecosystem classification that integrates saline and tidal freshwater reaches of estuaries in order to characterize the ecosystems of large flood plain rivers that are strongly influenced by riverine and estuarine hydrology. We illustrate the classification by applying it to the Columbia River estuary (Oregon-Washington, USA), a system that extends about 233 river kilometers (rkm) inland from the Pacific Ocean. More than three-quarters of this length is tidal freshwater. The Columbia River Estuary Ecosystem Classification ("Classification") is based on six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. We define and map Levels 1-3 for the entire Columbia River estuary with existing geospatial datasets, and provide examples of Levels 4-6 for one hydrogeomorphic reach. In particular, three levels of the Classification capture the scales and categories of ecosystem structure and processes that are most tractable to estuarine research, monitoring, and management. These three levels are the (1) eight hydrogeomorphic reaches that embody the formative geologic and tectonic processes that created the existing estuarine landscape and encompass the influence of the resulting physiography on interactions between fluvial and tidal hydrology and geomorphology across 230 kilometers (km) of estuary, (2) more than 15 ecosystem complexes composed of broad landforms created predominantly by geologic processes during the Holocene, and (3) more than 25 geomorphic catenae embedded within ecosystem complexes that represent distinct geomorphic landforms, structures, ecosystems, and habitats, and components of the estuarine landscape most likely to change over short time periods.

  15. Behaviour of Organic Carbon in Nine Contrasting European Estuaries

    NASA Astrophysics Data System (ADS)

    Abril, G.; Nogueira, M.; Etcheber, H.; Cabeadas, G.; Lemaire, E.; Brogueira, M. J.

    2002-02-01

    A cross-system comparison of organic carbon origin and behaviour in nine European estuaries is presented. The study sites display a very large range of hydrological and environmental conditions. The watershed of the respective estuaries were characterized by plotting the total organic carbon (TOC) in the rivers versus the inhabitants/discharge ratio. This allows to distinguish four types of watershed with regard to anthropogenic forcing and organic carbon levels: polluted by sewage inputs (Scheldt and to a much lesser extent, Ems, Sado and Thames), decontaminated (Elbe and Rhine), pristine (Gironde and Douro) and eutrophized (Loire and Scheldt). In the estuarine zone, dissolved organic carbon (DOC) almost always decreased linearly with increasing salinity. Exceptions were: the Scheldt, where a net consumption of sewage-derived DOC was observed, the Gironde, where a net production of DOC occurred in the maximum turbidity zone (MTZ) and the Sado and Ems, where DOC was supplied from large intertidal areas. By contrast, a large fraction of the riverine particulate organic carbon (POC) was mineralized in all the estuaries, except the Douro, where residence time of waters is only a few days. A fraction of POC appeared however refractory and accumulated in the MTZs, where terrestrial soil-derived material dominates (Elbe, Ems, Loire, Gironde and Sado). In the marine regions of most estuaries, autochthonous POC was present during spring and summer. The analysis of all river and estuarine data allows estimation of the loss of continental POC occurring in each estuary. It decreases in the following order: Scheldt?Thames>Ems=Sado=Loire>Gironde>Elbe>Rhine>Douro, which almost corresponds to the anthropogenic pressure in the respective watersheds. Two major variables appear to control the intensity of this mineralization: the origin of the POC, the lability increasing with pollution, and the residence time of particles in the estuarine zone.

  16. Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

    PubMed Central

    Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

    2016-01-01

    Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12–15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

  17. Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary.

    PubMed

    Lin, Xianbiao; Hou, Lijun; Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

    2016-01-01

    Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12-15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

  18. Salinity and turbidity distributions in the Brisbane River estuary, Australia

    NASA Astrophysics Data System (ADS)

    Yu, Yingying; Zhang, Hong; Lemckert, Charles

    2014-11-01

    The Brisbane River estuary (BRE) in Australia not only plays a vital role in ecosystem health, but is also of importance for people who live nearby. Comprehensive investigations, both in the short- and long-term, into the salinity and turbidity distributions in the BRE were conducted. Firstly, the analysis of numerical results revealed that the longitudinal salinity varied at approximately 0.45 and 0.61 psu/h during neap and spring tides, respectively. The turbidity stayed at a higher level and was less impacted by tide in the upper estuary, however, the water cleared up while the tide changed from flood to ebb in the mid and lower estuary. The second investigation into the seasonal variations of salinity and turbidity in the BRE was conducted, using ten-year field measurement data. A fourth-order polynomial equation was proposed, describing the longitudinal variation in salinity dilution changes as the upstream distance in the BRE during the wet and dry seasons. From the observation, the mid and upper estuaries were vertically well-mixed during both seasons, but the lower BRE was stratified, particularly during the wet season. The estuary turbidity maximum (ETM) zone was about 10 km longer during the wet season than the dry season. Particular emphasis was given to the third investigation into the use of satellite remote sensing techniques for estimation of the turbidity level in the BRE. A linear relationship between satellite observed water reflectance and surface turbidity level in the BRE was validated with an R2 of 0.75. The application of satellite-observed water reflectance therefore provided a practical solution for estimating surface turbidity levels of estuarine rivers not only under normal weather conditions, but also during flood events. The results acquired from this study are valuable for further hydrological research in the BRE and particularly prominent for immediate assessment of flood impacts.

  19. Distribution and Emission of Methane in Nakdong Estuary

    NASA Astrophysics Data System (ADS)

    Ryu, J.; An, S.

    2014-12-01

    Despite a small area, coastal areas contribute most to the oceanic methane flux. A wide range of methane fluxes have been reported in the coastal areas, but limited data were presented for Korean coastal areas. The air and surface water was sampled in Nakdong Estuary where the barrage had been constructed, and methane concentrations were measured using Gas Chromatography. To see the influence of the barrage, surface water was sampled outside and inside the barrage respectively. In the expectation that methane distribution would be different depending on the tides, surface water outside the barrage was collected at high and low tide respectively. Headspace technique and Membrane Inlet Mass Spectrometry were also used. The average atmospheric concentration (1.82ppm) was lower than the global average concentration expected from the IPCC scenario. The concentrations of water inside the barrage (average 173nM) were similar to those measured in other rivers but in the lower side. The average concentrations outside the barrage (52nM at high tide, 85nM at low tide) were lower than those measured in other coastal areas, but of the same order of magnitude as the European tidal estuaries. Methane concentrations in Nakdong estuary were higher than the methane concentration equilibrated with the atmosphere. The spatial variability of methane concentration in Nakdong estuary seems to be the result of the fresh (high methane) and sea (low methane) water mixing. Meanwhile large tidal flat area in Nakdong estuary should play a major role in methane dynamics and methane flux measurements during sediment incubation were conducted to evaluate the immersion/emersion cycle and photosynthesis by MPB (micro phyto benthos) effect.

  20. Biogeochemistry of nutrients in an estuary affected by human activities: The Wanquan River estuary, eastern Hainan Island, China

    NASA Astrophysics Data System (ADS)

    Li, Ruihuan; Liu, Sumei; Zhang, Guiling; Ren, Jingling; Zhang, Jing

    2013-04-01

    Nutrient dynamics were studied in the estuary of the Wanquan River, a tropical mountainous river system of Hainan Island, China, during 2006-2009. The nutrients measured included NO3-, NO2-, NH4+, PO43-, Si(OH)4, total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), dissolved organic nitrogen (DON), and dissolved organic phosphorus (DOP). The Wanquan River showed great variation in nutrient levels, was enriched in dissolved inorganic nitrogen (DIN) and dissolved silicate, and depleted in PO43-. The levels of dissolved silicate were higher than average for tropical systems. As a consequence the DIN:PO43- and Si(OH)4:DIN ratios were higher than the Redfield ratio. DON accounted for 18% of TDN in the Wanquan River, and DOP represented approximately 61% of TDP. Nutrients in the Wanquan River estuary behave either conservatively or nonconservatively. Nutrient biogeochemistry in the estuary is affected by human activities in adjacent areas and heavy rainfall associated with typhoons. Phosphorus may be the potential limiting nutrient for phytoplankton growth. A simple steady-state box model showed that riverine input was the major source of nutrients to the estuary, which acted as a source of all nutrients except dissolved silicate, TDP, and DOP. The results indicate that substantial quantities of nitrogen and PO43- are transported to the coastal system, and suggest that dissolved silicate accumulates in the sediment or is transformed into other forms.

  1. Building Regional Threat-Based Networks for Estuaries in the Western United States

    PubMed Central

    Merrifield, Matthew S.; Hines, Ellen; Liu, Xiaohang; Beck, Michael W.

    2011-01-01

    Estuaries are ecologically and economically valuable and have been highly degraded from both land and sea. Estuarine habitats in the coastal zone are under pressure from a range of human activities. In the United States and elsewhere, very few conservation plans focused on estuaries are regional in scope; fewer still address threats to estuary long term viability.We have compiled basic information about the spatial extent of threats to identify commonalities. To do this we classify estuaries into hierarchical networks that share similar threat characteristics using a spatial database (geodatabase) of threats to estuaries from land and sea in the western U.S.Our results show that very few estuaries in this region (16%) have no or minimal stresses from anthropogenic activity. Additionally, one quarter (25%) of all estuaries in this study have moderate levels of all threats. The small number of un-threatened estuaries is likely not representative of the ecological variability in the region and will require working to abate threats at others. We think the identification of these estuary groups can foster sharing best practices and coordination of conservation activities amongst estuaries in any geography. PMID:21387006

  2. Seasonal dynamics of meiofauna in a South African temporarily open/closed estuary (Mdloti Estuary, Indian Ocean)

    NASA Astrophysics Data System (ADS)

    Nozais, Christian; Perissinotto, Renzo; Tita, Guglielmo

    2005-01-01

    One hundred and eighty-four of the 250 estuaries in South Africa are currently classified as temporarily open/closed and close off from the sea during the dry season, under low river inflow. The subtropical Mdloti Estuary, on the KwaZulu-Natal north coast, is one of these systems and hardly any information is available on its meiofauna. The abundance, biomass, composition, and grazing impact of meiofauna, as well as the key environmental factors that affect these variables, were investigated with emphasis on the contrast between open and closed phases of the estuary. Microphytobenthic chlorophyll a concentrations varied between 1.4 to 480 mg m -2. Meiofauna were composed of nematodes, harpacticoid copepods, crustacean nauplii, mites, turbellarians, polychaetes, oligochaetes, ostracods and chironomids. Total abundance of meiofauna showed large variability both spatially and temporally and ranged from 0.4 to 8810 4 ind. m -2. Nematodes, mites and harpacticoid copepods occurred more often than other groups in the sediment. Total meiofauna carbon biomass exhibited similar temporal as well as spatial patterns as abundance and varied from 0.5 to 440 mg C m -2. A carbon-based grazing model, applied to the total meiofauna, provided estimates of potential daily ingestion rates ranging from 1.8 to 857 mg C m -2. Nematodes, mites and harpacticoid copepods contributed the most to the total potential daily ingestion rate of meiofauna in the Mdloti Estuary. Potential ingestion rates, determined using allometric equations, showed that meiofauna consumed from 0.1 to 254% of the microphytobenthic standing stock. Overall, meiofauna were likely not food limited and grazing on microphytobenthos was low, averaging 11% for the whole survey. A principal component analysis, applied to the whole study area and sampling period, indicated that major variations in meiofaunal community are mainly controlled by temperature and the state of the estuary's mouth (i.e. open/closed). Typically, meiofauna abundance in the estuary peaked after periods of prolonged mouth closure and decreased dramatically after the breaching of the estuary at the mouth.

  3. Ascent performance feasibility for next-generation spacecraft

    NASA Astrophysics Data System (ADS)

    Mancuso, Salvatore Massimo

    This thesis deals with the optimization of the ascent trajectories for single-stage suborbital (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem has been solved using the sequential gradient-restoration algorithm. For the TSTO case, some modifications to the original version of the algorithm have been necessary in order to deal with discontinuities due to staging and the fact that the functional being minimized depends on interface conditions. The optimization problem is studied for different values of the initial thrust-to-weight ratio in the range 1.3 to 1.6, engine specific impulse in the range 400 to 500 sec, and spacecraft structural factor in the range 0.08 to 0.12. For the TSTO configuration, two subproblems are studied: uniform structural factor between stages and nonuniform structural factor between stages. Due to the regular behavior of the results obtained, engineering approximations have been developed which connect the maximum payload weight to the engine specific impulse and spacecraft structural factor; in turn, this leads to useful design considerations. Also, performance sensitivity to the scale of the aerodynamic drag is studied, and it is shown that its effect on payload weight is relatively small, even for drag changes approaching 50%. The main conclusions are that: the design of a SSSO configuration appears to be feasible; the design of a SSTO configuration might be comfortably feasible, marginally feasible, or unfeasible, depending on the parameter values assumed; the design of a TSTO configuration is not only feasible, but its payload appears to be considerably larger than that of a SSTO configuration. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, it appears that aerodynamic improvements do not yield significant improvements in payload weight.

  4. Estuary Data Mapper: A Stand-Alone Tool for Geospatial Data Access, Visualization and Download for Estuaries and Coastal Watersheds of the United States. (UNH)

    EPA Science Inventory

    The US EPA Estuary Data Mapper (EDM; http://badger.epa.gov/rsig/edm/index.html) has been designed as a free stand-alone tool for geospatial data discovery, visualization, and data download for estuaries and their associated watersheds in the conterminous United States. EDM requi...

  5. Estuary Data Mapper: A Stand-Alone Tool for Geospatial Data Access, Visualization and Download for Estuaries and Coastal Watersheds of the United States

    EPA Science Inventory

    The US EPA Estuary Data Mapper (EDM; http://badger.epa.gov/rsig/edm/index.html) has been designed as a free stand-alone tool for geospatial data discovery, visualization, and data download for estuaries and their associated watersheds in the conterminous United States. EDM requi...

  6. Modeling ecosystem processes with variable freshwater inflow to the Caloosahatchee River Estuary, southwest Florida. I. Model development

    NASA Astrophysics Data System (ADS)

    Buzzelli, Christopher; Doering, Peter H.; Wan, Yongshan; Sun, Detong; Fugate, David

    2014-12-01

    Variations in freshwater inflow have ecological consequences for estuaries ranging among eutrophication, flushing and transport, and high and low salinity impacts on biota. Predicting the potential effects of the magnitude and composition of inflow on estuaries over a range of spatial and temporal scales requires reliable mathematical models. The goal of this study was to develop and test a model of ecosystem processes with variable freshwater inflow to the sub-tropical Caloosahatchee River Estuary (CRE) in southwest Florida from 2002 to 2009. The modeling framework combined empirically derived inputs of freshwater and materials from the watershed, daily predictions of salinity, a box model for physical transport, and simulation models of biogeochemical and seagrass dynamics. The CRE was split into 3 segments to estimate advective and dispersive transport of water column constituents. Each segment contained a sub-model to simulate changes in the concentrations of organic nitrogen and phosphorus (ON and OP), ammonium (NH4+), nitrate-nitrite (NOx-), ortho-phosphate (PO4-3), phytoplankton chlorophyll a (CHL), and sediment microalgae (SM). The seaward segment also had sub-models for seagrasses (Halodule wrightii and Thalassia testudinum). The model provided realistic predictions of ON in the upper estuary during wet conditions since organic nitrogen is associated with freshwater inflow and low salinity. Although simulated CHL concentrations were variable, the model proved to be a reliable predictor in time and space. While predicted NOx- concentrations were proportional to freshwater inflow, NH4+ was less predictable due to the complexity of internal cycling during times of reduced freshwater inflow. Overall, the model provided a representation of seagrass biomass changes despite the absence of epiphytes, nutrient effects, or sophisticated translocation in the formulation. The model is being used to investigate the relative importance of colored dissolved organic matter (CDOM) vs. CHL in submarine light availability throughout the CRE, assess if reductions in nutrient loads are more feasible by controlling freshwater quantity or N and P concentrations, and explore the role of inflow and flushing on the fates of externally and internally derived dissolved and particulate constituents.

  7. Response of the turbidity maximum zone to fluctuations in sediment discharge from river to estuary in the Changjiang Estuary (China)

    NASA Astrophysics Data System (ADS)

    Jiang, Xuezhong; Lu, Bing; He, Yuhong

    2013-10-01

    In the Changjiang Estuary, interactions between the sea and the river result in the development of a turbidity maximum zone (TMZ). Riverine sediments are an important source for TMZ formation. Since the 1960s, sediment discharge from the river basin to the estuary has decreased due to dam construction, water and soil conservation, and water diversion projects. Thirty-two Landsat images of the estuary, covering the period from 1979 to 2008, were collected to identify the TMZ response to sediment decline. A threshold value of suspended sediment concentration (SSC) of 0.7 kg/m3, corresponding to a spectrum reflectance of 5% of Landsat MSS band 7 and 7% of Landsat TM/ETM band 4, was used to identify the Changjiang Estuary TMZ. The TMZ area was then extracted from each image to investigate its temporal and spatial variations during the past 30 years. The images were grouped into five time series; the average TMZ area of each series was estimated. The results show that the TMZ area declined 23% from series (a) to series (e), responding to a 77% reduction in riverine sediment discharge. In addition, the TMZ had strong seasonal and tidal variations; it was generally larger during flood seasons than during dry seasons and during spring tides compared to neap tides. The spring/neap tidal cycle played a more important role in TMZ change than did the seasonal cycle. Due to the continued reduction of sediment discharge to the estuary resulting from dams already constructed and to those that will be constructed upstream in the Changjiang River, it is predicted that the TMZ area will continue decreasing and that the re-suspension of local sediments will play a more important role in the formation of the TMZ.

  8. Mercury methylation in the sediments of a macrotidal estuary (Gironde Estuary, south-west France)

    NASA Astrophysics Data System (ADS)

    Schfer, Jrg; Castelle, Sabine; Blanc, Grard; Dabrin, Aymeric; Masson, Matthieu; Lanceleur, Laurent; Bossy, Ccile

    2010-12-01

    Diagenetic behaviour of mercury species in surface sediments of the highly turbid Gironde Estuary was investigated along 6 vertical profiles, including the water-sediment interface (SWI) in dredged and non-dredged zones. Sediment and pore water were collected for analyses of major redox parameters ( e.g. dissolved Fe, Mn and sulphate), dissolved and particulate mono-methyl mercury (MeHg) and divalent mercury (Hg(II)). Concentrations of the dissolved Hg species were clearly (up to 70 times) higher in pore water than in the overlying water column, probably due to the dissolution or degradation of major Hg carrier phases such as Fe oxyhydroxides and particulate organic matter. The different profiles showed maximum MeHg D concentrations (up to 10 pmol L -1) and MeHg D/Hg D ratios (up to 40%) at a few cm below the SWI, suggesting intense in situ methylation processes for this zone. Depth-related methylation potential was investigated by spiking the cores with 199Hg(II) and their subsequent incubation. Methylation of isotopically labelled 199Hg(II) was measurable in all cores, suggesting that methylation in the studied sediments was efficient in the uppermost 20 cm below the SWI. The comparison between sediments retrieved inside and outside the navigation channel showed higher methylation potential in dredged sediments and in intertidal sediment, suggesting stimulation of the bacterial activity either by inputs ( e.g. fresh organic matter, sulphate) due to pore water renewal or by redox oscillation. The estimated MeHg D sediment-to-water flux was greater in non-dredged sediments, probably due to favourable anoxic conditions at the SWI. At the whole estuary scale, the estimated direct sediment to water transfer via passive diffusion was 1.1-2.7 mol yr -1 (210-55 g yr -1) for MeHg D and 3.8-4.0 mol yr -1 (750-790 g yr -1) for Hg(II) D, which is roughly equivalent to 15-50% and <3-12% of the respective annual fluvial gross inputs. The estimated dredging-related transfer of pore water Hg species to the water column appeared negligible (0.02 mol yr -1 (3.1 g yr -1) for MeHg D and 0.2 mol yr -1 (41 g yr -1) for Hg(II) D). Further work should aim at understanding the impact of suspending dredged anoxic sediments in the water column on the estuarine Hg cycle.

  9. Why Do Some Estuaries Close: A Model of Estuary Entrance Morphodynamics.

    NASA Astrophysics Data System (ADS)

    McSweeney, S. L.; Kennedy, D. M.; Rutherfurd, I.

    2014-12-01

    Intermittently Closed/Open Coastal Lakes/Lagoons (ICOLLs) are a form of wave-dominated, microtidal estuary that experience periodic closure in times of low river flow. ICOLL entrance morphodynamics are complex due to the interaction between wave, tidal and fluvial processes. Managers invest substantial funds to artificially open ICOLLs as they flood surrounding property and infrastructure, and have poor water quality. Existing studies examine broad scale processes but do not identify the main drivers of entrance condition. In this research, the changes in entrance geomorphology were surveyed before and after artificial entrance openings in three ICOLLs in Victoria, Australia. Changes in morphology were related to continuous measures of sediment volume, water level, tide and wave energy. A six-stage quantitative phase model of entrance geomorphology and hydrodynamics is presented to illustrate the spatio-temporal variability in ICOLL entrance morphodynamics. Phases include: breakout; channel expansion with rapid outflow; open with tidal exchange; initial berm rebuilding with tidal attenuation; partial berm recovery with rising water levels; closed with perched water levels. Entrance breakout initiates incision of a pilot channel to the ocean, whereby basin water levels then decline and channel expansion as the headcut migrates landwards. Peak outflow velocities of 5 m/s-3 were recorded and channel dimensions increased over 6 hrs to 3.5 m deep and 140 m wide. When tidal, a clear semi-diurnal signal is superimposed upon an otherwise stable water level. Deep-water wave energy was transferred 1.8 km upstream of the rivermouth with bores present in the basin. Berm rebuilding occurred by littoral drift and cross-shore transport once outflow ceased and microscale bedform features, particularly antidunes, contributed to sediment progradation. Phase duration is dependant on how high the estuary was perched above mean sea level, tidal prism extent, and onshore sediment supply. High offshore wave height and frequency, in addition to littoral drift magnitude, were main drivers of closure. This study presents a predictive model of entrance morphodynamics whereby managers can determine proximity to natural closure or opening, and as a result identify whether implementing an artificial opening is worthwhile.

  10. The Ichthyoplankton of Selected Estuaries in Sarawak and Sabah: Composition, Distribution and Habitat Affinities

    NASA Astrophysics Data System (ADS)

    Blaber, S. J. M.; Farmer, M. J.; Milton, D. A.; Pang, J.; Boon-Teck, O.; Wong, P.

    1997-08-01

    The ichthyoplankton assemblages of 23 estuaries in Sarawak and Sabah were surveyed with particular reference to the culturally and commercially important clupeid Tenualosa toli. The species composition, distribution and density of all fish larvae were recorded, together with the physical characteristics of each estuary. A more detailed study was made of the Lupar and Lassa estuaries, which are the ' core area ' for T. toli. The estuaries fall into two groups. The first consists of the estuaries of the ' core area ' from the Sebako in the west to the Lassa in the east, and the Labuk and Kinabatangan estuaries of eastern Sabah. They are large and deep, have middle-range salinities with no halocline, are highly turbid and have tidal ranges of >3·5 m and strong currents. There is little seasonal change in freshwater input and their waters are not peat-stained. Their total zooplankton biomasses (approximately 0·05 g m -3dry weight, excluding fish larvae) are an order of magnitude greater than biomasses in the second group of estuaries. The second group consists of all estuaries east of the Lassa as far as the Papar in Sabah. They are mostly smaller, shallower and have more variable salinities than the ' core area ' estuaries, with marked haloclines and seasonal changes in freshwater inflow, lower turbidities, weaker currents, tidal ranges of <2 m and low overall zooplankton biomasses. The composition of the ichthyoplankton is different in these two groups of estuaries. The assemblage in the first group (' core area ') of estuaries consists primarily of taxa associated with estuarine and/or turbid water conditions, whereas those in the smaller estuaries of the second group have mainly marine and clearer water affinities. Only the Gobiidae are ubiquitous. Very few larvae of freshwater species were recorded in any of the estuaries. The number of fish larvae was highly variable, but the mean densities (0·01-9·23 m -3) were similar, and similarly variable, to the densities reported for other tropical estuaries. The diversity of the ichthyoplankton assemblage in Sarawak and Sabah estuaries (56 taxa, 26 families) is lower than in most other tropical estuaries of the Indo-west Pacific. This is possibly because of their rigorous physical nature, particularly the very high turbidities and current speeds, or in smaller, less physically rigorous estuaries, the low biomass of zooplankton available as food for the larvae.

  11. Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program.

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2008-02-20

    The purpose of this document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program, hereafter called 'the Estuary Program'. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows: (1) Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. (2) Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. (3) Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. (4) Maintain the food web to benefit salmonid performance. (5) Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. The goal leads to three primary management questions pertaining to the main focus of the Estuary Program: estuary habitat conservation and restoration. (1) Are the estuary habitat actions achieving the expected biological and environmental performance targets? (2) Are the offsite habitat actions in the estuary improving juvenile salmonid performance and which actions are most effective at addressing the limiting factors preventing achievement of habitat, fish, or wildlife performance objectives? (3) What are the limiting factors or threats in the estuary/ocean preventing the achievement of desired habitat or fish performance objectives? Performance measures for the estuary are monitored indicators that reflect the status of habitat conditions and fish performance, e.g., habitat connectivity, survival, and life history diversity. Performance measures also pertain to implementation and compliance. Such measures are part of the monitoring, research, and action plans in this estuary RME document. Performance targets specific to the estuary were not included in the 2007 draft Biological Opinion.

  12. Stirling Engine Heat Pump

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru

    Recent advances in the feasibility studies related to the Stirling engines and Stirling engine heat pumps which have been considered attractive due to their promising role in helping to solve the global environmental and energy problems,are reviewed. This article begins to describe the brief history of the Stirling engines and theoretical thermodynamic analysis of the Stirling cycle in order to understand several advantages on the Stirling engine. Furthermore,they could throw light on our question why the dream engines had not been promoted to practical applications during two hundred years. The present review shows that the Stirling engines with several unique advantages including 30 to 40% thermal efficiency and preferable exhaust characteristics,had been designed and constructed by recent tackling for the development of the advanced automobile and other applications using them. Based on the current state of art,it is being provided to push the Stirling engines combined with heat pumps based on the reversed Rankine cycle to the market. At present,however, many problems, especially for the durability, cost, and delicate engine parts must be enforced to solve. In addition,there are some possibilities which can increase the attractiveness of the Stirling engines and heat pumps. The review closes with suggestions for further research.

  13. Feasibility analysis of recycling radioactive scrap steel

    SciTech Connect

    Nichols, F.; Balhiser, B.; Cignetti, N.

    1995-09-01

    The purpose of this study is to: (1) establish a conceptual design that integrates commercial steel mill technology with radioactive scrap metal (RSM) processing to produce carbon and stainless steel sheet and plate at a grade suitable for fabricating into radioactive waste containers; (2) determine the economic feasibility of building a micro-mill in the Western US to process 30,000 tons of RSM per year from both DOE and the nuclear utilities; and (3) provide recommendations for implementation. For purposes of defining the project, it is divided into phases: economic feasibility and conceptual design; preliminary design; detail design; construction; and operation. This study comprises the bulk of Phase 1. It is divided into four sections. Section 1 provides the reader with a complete overview extracting pertinent data, recommendations and conclusions from the remainder of the report. Section 2 defines the variables that impact the design requirements. These data form the baseline to create a preliminary conceptual design that is technically sound, economically viable, and capitalizes on economies of scale. Priorities governing the design activities are: (1) minimizing worker exposure to radionuclide hazards, (2) maximizing worker safety, (3) minimizing environmental contamination, (4) minimizing secondary wastes, and (5) establishing engineering controls to insure that the plant will be granted a license in the state selected for operation. Section 3 provides details of the preliminary conceptual design that was selected. The cost of project construction is estimated and the personnel needed to support the steel-making operation and radiological and environmental control are identified. Section 4 identifies the operational costs and supports the economic feasibility analysis. A detailed discussion of the resulting conclusions and recommendations is included in this section.

  14. Distinguishing resuspension and advection signals in a hypertidal estuary

    NASA Astrophysics Data System (ADS)

    Todd, David; Souza, Alex; Jago, Colin

    2015-04-01

    Terrestrial material is supplied to an estuary system by the river, while marine material is supplied by the sea. Whether the estuary acts as a trap or a bypass zone for SPM (suspended particulate matter) depends upon the properties and dynamics of both the estuary, including the tidal and residual behaviour of the currents, and the SPM, including particle sizes and settling velocities and concentration gradients, which together control the dynamics, such as the trapping efficiency, of the estuary. Whether an SPM signal is regarded as being one of resuspension or advection depends upon the area of interest, and therefore distinguishing between resuspension and advection can be complex. Material that is resuspended within the area of study is regarded as resuspension, while that which is resuspended outside, but passes through, the area of interest, is regarded as advection. The results of a measurement campaign undertaken in a hypertidal UK estuary during the pre-spring bloom February-March and post-spring bloom May-June are presented utilising a combination of acoustic and optical instruments, moorings, and CTD stations. A characteristic asymmetric "twin peak" signal is present during both time periods, implying the presence of both resuspension and advection. This is confirmed through the use of harmonic analysis. A seasonal variation in the relative importance of the resuspension and advection components is seen between the two observation periods, with the small (<122µm) and large (>122µm) particles displaying different behaviours and providing a strong indication of the presence of flocculation. Approximate point flux calculations showed a reduction in the horizontal gradient of concentration, and subsequently the flood dominance of sediment transport, between May-June and February-March. This has been attributed to changes in biological activity and atmospheric forcing between the two observational periods. Ebb-dominant concentrations brought about by the horizontal concentration gradient were opposed by a possible asymmetrical flocculation signal with asymmetrically larger particles occurring during low water than high water. This led to faster settling particles at low water and therefore, over time, a tidal pumping mechanism which transports material up the estuary.

  15. Plastic pollution in five urban estuaries of KwaZulu-Natal, South Africa.

    PubMed

    Naidoo, Trishan; Glassom, David; Smit, Albertus J

    2015-12-15

    Monitoring plastic concentrations in estuaries is vital in assessing the magnitude of terrestrial inputs to oceanic environments. Data on plastics ?5mm in estuaries are scant. This study determined microplastic levels within five estuaries along the Durban coastline and on intervening beaches. Plastics were isolated from estuarine sediment, beach sediment and the surface water of each estuary and characterised. Sediment at the Bayhead area of Durban harbour had the highest average plastic concentrations (745.4129.7 particles per 500ml) and an attenuating concentration trend away from the city centre was found. Prevailing south to north longshore drift was hypothesised to result in plastic accumulation on the northern shores of beaches with estuarine effluents, however, this was not found. Fragments composed the largest percent of plastics (59%) found in Bayhead, whereas fibres dominated other estuaries with proportions ranging from 38% of total plastics in the uMgeni estuary to 66% in the Mdloti. PMID:26476863

  16. Comparative Effects of Pulsed Fluvial and Meteorological Forcing on Hydrologic Circulation and Sediment Flux in a Louisiana Deltaic Estuary

    NASA Astrophysics Data System (ADS)

    Snedden, G. A.; Cable, J. E.; Swenson, E. M.; Swarzenski, C.

    2002-05-01

    Water and sediment flux in subestuaries of the Mississippi River deltaic plain are dictated by a variety of factors, particularly freshwater input and meteorological forcing. Often, these events occur as discrete, sometimes extreme, pulsed events and their resultant impacts on water and materials flux may be equally marked. Whereas these pulsed events are regarded as vital to wetland function and structure, their contributions to deltaic estuaries in Louisiana may be inhibited or enhanced by human-induced landscape alterations such as containment levees and dams. To help restore hydrologic integrity to some Louisiana estuaries, river diversion projects are employed to replace fluvial inputs that were once eliminated by these engineering projects on the Mississippi River. We evaluated time-series data of discharge and turbidity at multiple sites in Breton Sound, the receiving basin of a Mississippi River diversion, to examine the importance of riverine inflows relative to meteorological events on the hydrologic function of this estuary. During two 15-day high-capacity (Q = 170 m3 s-1) diversion events in early 2002, fluvial sediment influxes exceeded 30 kg s-1. Decreased sediment influxes (<1 kg s-1) were associated with reduced diversion discharge (Q = 15 m3 s-1). Meteorological forcing caused strong increases in sediment loads, but changes were relatively ephemeral, and overall changes in sediment flux were less than those induced by fluvial inputs through the diversion structure. Preliminary analysis of sediment transport mass balance revealed that almost 25% of sediments introduced during the high-capacity diversion events escaped channels and were transported over the marsh surface as sheet flow.

  17. Contemporary distribution of macrozoobenthic communities of the Yeisk estuary (Taganrog Bay of the Sea of Azov)

    NASA Astrophysics Data System (ADS)

    Nabozhenko, M. V.; Kovalenko, E. P.

    2011-08-01

    The contemporary distribution of macrozoobenthic communities of the Yeisk estuary is considered. Four basic types of communities are classified. Communities with domination of Tubificidae (Oligochaeta) occupy the greatest part of the estuary. Communities with domination of Amphipoda (Corophiidae) remained only in the northeast part of the reservoir. The unstable hydrological conditions and the absence of clearly expressed horohalinicum lead to mixing of Ponto-Caspian and Azov-Black Sea faunas in the Yeisk estuary.

  18. Physical, hydrological, and biological characteristics of the Loxahatchee River estuary, Florida

    USGS Publications Warehouse

    McPherson, Benjamin F.; Sabanskas, Maryann; Long, William Atwood

    1982-01-01

    The Loxahatchee River estuary in southeast Florida has periodically closed and opened to the sea as a result of natural causes. In the last 30 years, the estuary has remained open only by dredging. Activities of man in the estuary and basin affect freshwater and tidal flow which in turn affect bathymetry, bottom sediment, and biota. Under present conditions, tidal flow is much larger than freshwater inflow. (USGS)

  19. Phosphatase activities in the waters of a shallow estuary, Western Australia

    NASA Astrophysics Data System (ADS)

    Huber, A. L.; Gabrielson, J. O.; Kidby, D. K.

    1985-10-01

    Phosphatase activities in a large, shallow estuary in south western Western Australia have been assessed. Differences were found in enzyme activities in the two sections of the estuary. There were seasonal and diurnal variations as well. Phosphatase activities were most closely correlated with chlorophyll and organic nitrogen concentrations. In diurnal studies, the rates of change of phosphatase activity corresponded with the rates of change in orthophosphate. The role of phosphatase activity in regeneration of esterified phosphorus in the estuary is discussed.

  20. Subtidal sea level variability in a shallow Mississippi River deltaic estuary, Louisiana

    USGS Publications Warehouse

    Snedden, G.A.; Cable, J.E.; Wiseman, W.J., Jr.

    2007-01-01

    The relative roles of river, atmospheric, and tidal forcings on estuarine sea level variability are examined in Breton Sound, a shallow (0.7 m) deltaic estuary situated in an interdistributary basin on the Mississippi River deltaic plain. The deltaic landscape contains vegetated marshes, tidal flats, circuitous channels, and other features that frictionally dissipate waves propagating through the system. Direct forcing by local wind stress over the surface of the estuary is minimal, owing to the lack of significant fetch due to landscape features of the estuary. Atmospheric forcing occurs almost entirely through remote forcing, where alongshore winds facilitate estuary-shelf exchange through coastal Ekman convergence. The highly frictional nature of the deltaic landscape causes the estuary to act as a low-pass filter to remote atmospheric forcing, where high-frequency, coastally-induced fluctuations are significantly damped, and the damping increases with distance from the estuary mouth. During spring, when substantial quantities of controlled Mississippi River inputs (q?? = 62 m3 s-1) are discharged into the estuary, upper estuary subtidal sea levels are forced by a combination of river and remote atmospheric forcings, while river effects are less clear downestuary. During autumn (q?? = 7 m3 s-1) sea level variability throughout the estuary is governed entirely by coastal variations at the marine boundary. A frequency-dependent analytical model, previously used to describe sea level dynamics forced by local wind stress and coastal forcing in deeper, less frictional systems, is applied in the shallow Breton Sound estuary. In contrast to deeper systems where coastally-induced fluctuations exhibit little or no frictional attenuation inside the estuary, these fluctuations in the shallow Breton Sound estuary show strong frequency-dependent amplitude reductions that extend well into the subtidal frequency spectrum. ?? 2007 Estuarine Research Federation.

  1. Response of Nereis diversicolor population (Polychaeta, Nereididae) to the pollution impact - Authie and Seine estuaries (France)

    NASA Astrophysics Data System (ADS)

    Gillet, P.; Mouloud, M.; Durou, C.; Deutsch, B.

    2008-01-01

    A survey within the French National Programme of Ecotoxicology was carried out in 2002, 2003 and 2004 to study the response of Nereis diversicolor populations (Polychaeta, Nereididae) to the impact of pollution in the Authie estuary (non-contaminated site) and in the Seine estuary (contaminated site). In the period studied, the density varied from 672 ind. m -2 to 3584 ind. m -2 in the Authie estuary and from 80 ind. m -2 to 920 ind. m -2 in the Seine estuary. Biomass varied from 3.94 g m -2 (dry weight) in February 2004 to 38.0 g m -2 in August 2003 in the Authie estuary and from 3.4 g m -2 in February 2002 to 0.6 g m -2 in February 2004 in the Seine estuary. Density and biomass of the populations of N. diversicolor were consistently lower in the Seine estuary than in the Authie estuary. Size frequency histograms permit the analysis of the cohorts as well as the elaboration of the growth curves. For the individuals from the Authie estuary, the relation between dry weight (DW) and length L3 (prostomium, peristomium and chaetiger 1) was DW = 4.2205 L3 2.9832. For those from the Seine estuary, the relation between dry weight and L3 was DW = 0.4697e 1.7209L3. The individuals of N. diversicolor should belong to eight cohorts in Authie estuary (two cohorts each year) instead of six cohorts for those from the Seine estuary. These differences can be attributed to the effect of pollution on the population of N. diversicolor.

  2. Distribution and sources of particulate organic matter in the Indian monsoonal estuaries during monsoon

    NASA Astrophysics Data System (ADS)

    Sarma, V. V. S. S.; Krishna, M. S.; Prasad, V. R.; Kumar, B. S. K.; Naidu, S. A.; Rao, G. D.; Viswanadham, R.; Sridevi, T.; Kumar, P. P.; Reddy, N. P. C.

    2014-11-01

    The distribution and sources of particulate organic carbon (POC) and nitrogen (PN) in 27 Indian estuaries were examined during the monsoon using the content and isotopic composition of carbon and nitrogen. Higher phytoplankton biomass was noticed in estuaries with deeper photic zone than other estuaries receiving higher suspended matter. The ?13CPOC and ?15NPN data suggest that relatively higher ?13CPOC (-27.9 to -22.6) and lower ?15NPN (0.7 to 5.8) were noticed in the estuaries located in the northern India, north of 16N, and lower ?13CPOC (-31.4 to -28.2) and higher ?15NPN (5 to 10.3) in the estuaries located in the southern India. This is associated with higher Chl a in the northern than southern estuaries suggesting that in situ production contributed significantly to the POC pool in the former, whereas terrestrial sources are important in the latter estuaries. The spatial distribution pattern of ?15NPN is consistent with fertilizer consumption in the Indian subcontinent, which is twice as much in the northern India as in the south whereas ?13CPOC suggests that in situ production is a dominant source in the southern and terrestrial sources are important in the northern estuaries. Based on the Stable Isotope Analysis in R model, 40-90% (70-90%) of organic matter is contributed by C3 plants (freshwater algae) in the estuaries located in the northern (southern) India.

  3. Where river and tide meet: The morphodynamic equilibrium of alluvial estuaries

    NASA Astrophysics Data System (ADS)

    Bolla Pittaluga, Michele; Tambroni, Nicoletta; Canestrelli, Alberto; Slingerland, Rudy; Lanzoni, Stefano; Seminara, Giovanni

    2015-01-01

    We investigate the morphodynamic equilibrium of tidally dominated alluvial estuaries, extending previous works concerning the purely tidal case and the combined tidal-fluvial case with a small tidal forcing. We relax the latter assumption and seek the equilibrium bed profile of the estuary, for a given planform configuration with various degrees of funneling, solving numerically the 1-D governing equation. The results show that with steady fluvial and tidal forcings, an equilibrium bed profile of estuaries exists. In the case of constant width estuaries, a concave down equilibrium profile develops through most of the estuary. Increasing the amplitude of the tidal oscillation, progressively higher bed slopes are experienced at the mouth while the river-dominated portion of the estuary experiences an increasing bed degradation. The fluvial-marine transition is identified by a "tidal length" that increases monotonically as the river discharge and the corresponding sediment supply are increased while the river attains a new morphological equilibrium configuration. Tidal length also increases if, for a fixed river discharge and tidal amplitude, the sediment flux is progressively reduced with respect to the transport capacity. In the case of funnel-shaped estuaries the tidal length strongly decreases, aggradation is triggered by channel widening, and tidal effects are such to enhance the slope at the inlet and the net degradation of the river bed. Finally, results suggest that alluvial estuaries in morphological equilibrium cannot experience any amplification of the tidal wave propagating landward. Hence, hypersynchronous alluvial estuaries cannot be in equilibrium.

  4. Circulation and physical processes within the San Gabriel River Estuary during summer 2005

    USGS Publications Warehouse

    Rosenberger, Kurt J.; Xu, Jingping; Stein, Eric D.; Noble, Marlene A.; Gartner, Anne L.

    2007-01-01

    The Southern California Coastal Water Research Project (SCCWRP) is developing a hydrodynamic model of the SGR estuary, which is part of the comprehensive water-quality model of the SGR estuary and watershed investigated by SCCWRP and other local agencies. The hydrodynamic model will help understanding of 1) the exchange processes between the estuary and coastal ocean; 2) the circulation patterns in the estuary; 3) upstream natural runoff and the cooling discharge from PGS. Like all models, the SGR hydrodynamic model is only useful after it is fully calibrated and validated. In May 2005, SCCWRP requested the assistance of the U.S. geological Survey (USGS) Coastal and Marine Geology team (CMG) in collecting data on the hydrodynamic conditions in the estuary during the summer dry season. The summer was chosen for field data collection as this was assumed to be the season with the greatest potential for chronic degraded water quality due to low river flow and high thermal stratification within the estuary (due to both higher average air temperature and PGS output). Water quality can be degraded in winter as well, when higher river discharge events bring large volumes of water from the Los Angeles basin into the estuary. The objectives of this project were to 1) collect hydrodynamic data along the SGR estuary; 2) study exchange processes within the estuary through analysis of the hydrodynamic data; and 3) provide field data for model calibration and validation. As the data only exist for the summer season, the results herein only apply to summer conditions.

  5. Using a Multi-Component Indicator Toward Reducing Phytoplankton Bloom Occurrences in the Swan River Estuary

    NASA Astrophysics Data System (ADS)

    Kristiana, Ria; Antenucci, Jason P.; Imberger, Jorg

    2012-08-01

    The Swan River estuary is an icon of the city of Perth, Western Australia, running through the city centre and dividing the northern from the southern part of the city. However, frequent phytoplankton blooms have been observed in the estuary as a result of eutrophication. The Index of Sustainable Functionality (ISF), a composite index able to indicate for sustainable health of the estuary, was applied, taking into account the hydrology and highly seasonal nature of the estuary to inform the management of the estuary, towards the aim of reducing bloom occurrences. The study period was from the beginning of intensive monitoring in 1995 to mid-2009. The results emphasize the importance of physical controls on the ecology of the estuary. No significant trend in the estuary's low functionality was found, indicating that despite extensive restoration efforts, the frequency of algal bloom occurrences has remained relatively stationary and other mitigating factors have maintained an annual average ISF value at around 70 % functionality. We identified that the low flow season consistently performs the worst, with (high) temperature found as the most dominant variable for phytoplankton growth and bloom. Thus in managing the estuary, vigilance is required during periods of high temperature and low flow. Focusing on the risk of phytoplankton bloom, a nutrient reduction program that is in place is a long term solution due to high concentrations in the estuary. Other management measures need to be considered and adopted to effectively reduce the occurrences of future phytoplankton blooms.

  6. Using a multi-component indicator toward reducing phytoplankton bloom occurrences in the Swan River estuary.

    PubMed

    Kristiana, Ria; Antenucci, Jason P; Imberger, Jorg

    2012-08-01

    The Swan River estuary is an icon of the city of Perth, Western Australia, running through the city centre and dividing the northern from the southern part of the city. However, frequent phytoplankton blooms have been observed in the estuary as a result of eutrophication. The Index of Sustainable Functionality (ISF), a composite index able to indicate for sustainable health of the estuary, was applied, taking into account the hydrology and highly seasonal nature of the estuary to inform the management of the estuary, towards the aim of reducing bloom occurrences. The study period was from the beginning of intensive monitoring in 1995 to mid-2009. The results emphasize the importance of physical controls on the ecology of the estuary. No significant trend in the estuary's low functionality was found, indicating that despite extensive restoration efforts, the frequency of algal bloom occurrences has remained relatively stationary and other mitigating factors have maintained an annual average ISF value at around 70 % functionality. We identified that the low flow season consistently performs the worst, with (high) temperature found as the most dominant variable for phytoplankton growth and bloom. Thus in managing the estuary, vigilance is required during periods of high temperature and low flow. Focusing on the risk of phytoplankton bloom, a nutrient reduction program that is in place is a long term solution due to high concentrations in the estuary. Other management measures need to be considered and adopted to effectively reduce the occurrences of future phytoplankton blooms. PMID:22669343

  7. Multibiomarker assessment of three Brazilian estuaries using oysters as bioindicators.

    PubMed

    Valdez Domingos, F X; Azevedo, M; Silva, M D; Randi, M A F; Freire, C A; Silva de Assis, H C; Oliveira Ribeiro, C A

    2007-11-01

    Oysters have been largely employed as bioindicators of environmental quality in biomonitoring studies. Crassostrea rhizophorae was selected to evaluate the health status of three estuarine areas impacted by anthropogenic activities along the Brazilian coast, in three estuarine complexes, ranging in latitude from 7 to 25 degrees S. In each estuary three sites were sampled in Winter and in Summer: a site considered as reference, and two sites next to contamination sources. Condition index was similar at all sites and estuaries, with the highest values found for Itamarac oysters in Summer. Necrosis, hyperplasia, mucocyte hypertrophy and fusion of ordinary filaments were the main histopathological lesions observed. Muscle cholinesterase activity was overall similar, but with a strong seasonal effect. Inhibition or activation of branchial total ATPase and Na,K-ATPase activities at the contaminated sites was observed. The health status of these estuarine areas is quite similar, and the combined use of biomarkers is recommended. PMID:17658507

  8. Decadal to Millennial Sedimentation Patterns of the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Jones, M.; McHugh, C. M.; Burckle, L.; Pekar, S.; Pereira, G.; Ryan, W. B.; Bell, R.; Carbotte, S.

    2002-12-01

    The Hudson River Estuary (HRE) is adjacent to large metropolitan areas including New York City. Understanding the variable energy conditions for transporting sediments is key to deal with environmental pollution such as the controversial burial and dredging of PCB's in the HRE. We studied sediment transport in the HRE by examining more than 150 cores and grab samples interpreted within the framework of acoustic images. The HRE sedimentary environments were defined based on quantitative estimates of grain size, sedimentary structures, bioturbation, and sedimentation rates and were divided into: channel, channel banks, subtidal flats, tributaries, and islands. Diatom assemblages were used to determine the extent of salt-water intrusion and sediment reworking in the estuary. Along a longitudinal profile, the estuary can be subdivided into: (1) sandy inner fluvial (furthest upstream), (2) muddy central portions, and (3) sandy outer marine. We classified sedimentary facies for the central and fluvial parts of the system (1 and 2). The HRE basin is nearly filled with sediment and tidal energy is focused within the channel and its banks. In the central basin where the estuary is wide (up to 4 km), flood currents are more energetic along the eastern channel bank and the ebb currents lead to minor sediment deposition on the western bank, but only where the system is out of equilibrium with its sediment load. The energy of the tides is accentuated along narrow segments of the estuary that are locally constrained by gorges of the Hudson Valley Highlands leading to erosion and the trapping of sediments. Beyond the banks of the channel, the subtidal flats that were filled with sediment by 0.5 to 3ka, are tranquil environments where the sediment is homogenized by bioturbation and reworked by waves as the estuary shallowed. Occasional high-energy events, (possibly flood-related) eroded the subtidal flats sediment as shown by rare rip-up clasts found in the cores. The inner fluvial part of the estuary is filling with sediments above sea-level forming islands. Here, the energy of tidal currents is strong as evidenced by the sand-mud rhythmic alternations of the sediments. Tributaries contribute a generally low sediment budget, but only on a seasonal basis and the fluvial energy is not strong enough to transport the gravel-size components that remain near the mouths of the tributaries forming localized deltas. The fluvial sands, form waves that migrate along the channel floor, but this coarser-grained bedload is rarely transported south of Kingston, New York, resulting in a muddy estuarine bottom further downstream. Results show that tidal energy is a dominant force in the transport and deposition of HRE sediments and that only fine-grained sediments are transported throughout most of the studied areas. Because the HRE basin is nearly filled, most sediment bypasses the system with only localized areas of sediment trapping where the estuary is out of equilibrium with its sediment load, and in the estuarine turbidity maxima, an area previously shown to contain high sediment concentrations.

  9. Estimation of bed shear stresses in the pearl river estuary

    NASA Astrophysics Data System (ADS)

    Liu, Huan; Wu, Jia-xue

    2015-03-01

    Mean and fluctuating velocities were measured by use of a pulse coherent acoustic Doppler profiler (PC-ADP) and an acoustic Doppler velocimeter in the tidal bottom boundary layer of the Pearl River Estuary. The bed shear stresses were estimated by four different methods: log profile (LP), eddy correlation (EC), turbulent kinetic energy (TKE), and inertial dissipation (ID). The results show that (a) all four methods for estimating bed stresses have advantages and disadvantages, and they should be applied simultaneously to obtain reliable frictional velocity and to identify potential sources of errors; (b) the LP method was found to be the most suitable to estimate the bed stresses in non-stratified, quasi-steady, and homogeneous flows; and (c) in the estuary where the semi-diurnal tidal current is dominant, bed shear stresses exhibit a strong quarter-diurnal variation.

  10. Leukaemia incidence, social class and estuaries: an ecological analysis.

    PubMed

    Alexander, F E; Cartwright, R A; McKinney, P A; Ricketts, T J

    1990-01-01

    Leukaemia incidence data for 1984-1986 for 22 counties of England and Wales have been collected by a specialist registry. The present study is an ecological analysis in which incidence in electoral wards has been tested for association with two predefined ward characteristics: socio-economic status and proximity to estuaries. Small but statistically significant associations have been observed with relative risks in the range 1.05-1.50. Adjustments have been made in the analysis for variation in the underlying regional incidence and also for statistical artefacts consequent upon the rarity of the condition. The results for socio-economic status confirm those of other recent studies, with increased incidence linked to higher status. The results for estuaries are new although derived from a prior hypothesis. PMID:2223195

  11. Clostridium botulinum type C in the Mersey estuary.

    PubMed Central

    Smith, G. R.; Oliphant, J. C.; White, W. R.

    1982-01-01

    Nineteen of 98 samples of mud or sand taken from the Mersey estuary in 1981 contained Clostridium botulinum type C, the organism almost always responsible for botulism in water birds. In the Dungeon and Score Bank areas, where many dead and dying birds were found during the period September-December 1979, almost half the samples contained type C. Most of the positive samples were essentially muddy rather than sandy. The findings do not prove that botulism contributed to the 1979 mortality but are nonetheless thought-provoking, particularly because type C--unlike type B--is by no means ubiquitous in Britain. Type B was present in 12.2% of samples from the Mersey estuary. PMID:6759578

  12. Ecological quality assessment of the lower Lima Estuary.

    PubMed

    Costa-Dias, Srgia; Sousa, Ronaldo; Antunes, Carlos

    2010-01-01

    Monitoring biotic factors is gaining in importance within Europe, due in large extent to the ecological approach of the European Water Framework Directive (WFD) and the importance attributed to biological elements in the assessment of quality status. Despite its ecological importance, the Lima Estuary is subjected to a range of perturbations, including urban, agricultural and industrial waste discharge, dredging activities, and introduction of non-indigenous invasive species. This work uses macrozoobenthic data to study the ecological status of the lower Lima Estuary where most disturbance factors are concentrated. We were able to verify consistent differences along space, and to identify different degrees of disturbance in the estuarine area. These results allow us to suggest cost-effective approaches to monitor this estuarine area, aiming on contributing to effective management actions. PMID:20347451

  13. Effects of Prevailing Winds on Turbidity of a Shallow Estuary

    PubMed Central

    Cho, Hyun Jung

    2007-01-01

    Estuarine waters are generally more turbid than lakes or marine waters due to greater algal mass and continual re-suspension of sediments. The varying effects of diurnal and seasonal prevailing winds on the turbidity condition of a wind-dominated estuary were investigated by spatial and statistical analyses of wind direction, water level, turbidity, chlorophyll a, and PAR (Photosynthetically Active Radiation) collected in Lake Pontchartrain, Louisiana, USA. The prolonged prevailing winds were responsible for the long-term, large-scale turbidity pattern of the estuary, whereas the short-term changes in wind direction had differential effects on turbidity and water level in varying locations. There were temporal and spatial changes in the relationship between vertical light attenuation coefficient (Kd) and turbidity, which indicate difference in phytoplankton and color also affect Kd. This study demonstrates that the effect of wind on turbidity and water level on different shores can be identified through system-specific analyses of turbidity patterns. PMID:17617683

  14. Multibiomarker assessment of three Brazilian estuaries using oysters as bioindicators

    SciTech Connect

    Valdez Domingos, F.X. Azevedo, M.; Silva, M.D.; Randi, M.A.F.; Freire, C.A.; Silva de Assis, H.C.; Oliveira Ribeiro, C.A.

    2007-11-15

    Oysters have been largely employed as bioindicators of environmental quality in biomonitoring studies. Crassostrea rhizophorae was selected to evaluate the health status of three estuarine areas impacted by anthropogenic activities along the Brazilian coast, in three estuarine complexes, ranging in latitude from 7 to 25 deg. S. In each estuary three sites were sampled in Winter and in Summer: a site considered as reference, and two sites next to contamination sources. Condition index was similar at all sites and estuaries, with the highest values found for Itamaraca oysters in Summer. Necrosis, hyperplasia, mucocyte hypertrophy and fusion of ordinary filaments were the main histopathological lesions observed. Muscle cholinesterase activity was overall similar, but with a strong seasonal effect. Inhibition or activation of branchial total ATPase and Na,K-ATPase activities at the contaminated sites was observed. The health status of these estuarine areas is quite similar, and the combined use of biomarkers is recommended.

  15. Assessment of sediment contaminants and toxicity in the Delaware estuary

    SciTech Connect

    Costa, H.J.; Sauer, T.C.; Ward, T.J.; Boeri, R.L.; Nyman, R.M.

    1994-12-31

    In support of the Delaware Estuary Program`s Comprehensive Conservation and Management Plan, a study was performed to assess the spatial distribution of sediment toxicity in the Delaware Estuary and investigate potential causative contaminants. Twelve stations were sampled along the Delaware River covering 55 river miles between the Chesapeake and Delaware Canal and Torresdale, PA. Four additional stations were sampled in the mid-bay portion of Delaware Bay. Ten-day sediment static acute toxicity tests with amphipods (Ampelisca abdita) were performed for all stations. Sediments were analyzed for polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls, chlorinated pesticides, priority pollutant metals, and supporting parameters. Statistical analyses revealed positive correlations between sediment toxicity and PAH, lead, copper, and mercury concentrations. The highest incidences of sediment toxicity and highest concentrations of chemical contaminants occurred in the portion of the Delaware River between River Miles 60 and 75.

  16. KE Basin water dispositioning engineering study

    SciTech Connect

    Hunacek, G.S.; Gahir, S.S.

    1994-09-23

    This engineering study is a feasibility study of KE Basin water treatment to an acceptable level and dispositioning the treated water to Columbia River, ground through ETF or to air through evaporation.

  17. Sedimentary framework of the Potomac River estuary, Maryland

    USGS Publications Warehouse

    Knebel, Harley J.; Martin, E. Ann; Glenn, J.L.; Needell, Sally W.

    1981-01-01

    Analyses of seismic-reflection profiles, sediment cores, grab samples, and side-scan sonar records, along with previously collected borehole data, reveal the characteristics, distribution, and geologic history of the shallow strata beneath the Potomac River estuary. The lowermost strata are sediments of the Chesapeake Group (lower Miocene to lower Pleistocene) that crop out on land near the shore but are buried as much as 40 m below the floor of the estuary. The top of these sediments is an erosional unconformity that outlines the Wisconsinan valley of the Potomac River. This valley has a sinuous trend, a flat bottom, a relief of 15 to 34 m, and axial depths of 34 to 54 m below present sea level. During the Holocene transgression of sea level, the ancestral valley was filled with as much as 40 m of sandy and silty, fluvial-to-shallow estuarine sediments. The fill became the substrate for oyster bars in the upper reach and now forms most marginal slopes of the estuary. Since sea level approached its present position (2,000 to 3,000 yr ago), the main channel has become the locus of deposition for watery, gray to black clay or silty clay, and waves and currents have eroded the heterogeneous Quaternary sediments along the margins, leaving winnowed brown sand on shallow shoreline flats. Pb-210 analyses indicate that modern mud is accumulating at rates ranging from 0.16 to 1.80 cm/yr, being lowest near the mouth and increasing toward the head of the estuary. This trend reflects an increased accumulation of fine-grained fluvial sediments near the turbidity maximum, similar to that found in nearby Chesapeake Bay. The present annual accumulation of mud is about 1.54 million metric tons; the cumulative mass is 406 million metric tons.

  18. Residence time of water in the Mondego estuary (Portugal)

    NASA Astrophysics Data System (ADS)

    Ascione Kenov, Isabella; Garcia, Ana Carla; Neves, Ramiro

    2012-06-01

    The residence time of water is widely used as an indicator of how long a substance will remain in an estuary, a harbour, or a lagoon, and it is used to enable comparisons among different water bodies. In this work, the residence time in the Mondego Estuary, Portugal, is calculated by using two methodologies: the first one is based on field data and a freshwater fraction model, and the second one is based on a Lagrangian transport model. The Lagrangian model is coupled to a two-dimensional hydrodynamic numerical model that solves the depth-averaged advection and diffusion equations. Boundary conditions are provided by the Portuguese Coastal Operational Model, downscaled by using four nested domains with increasing resolution from the large to the local scale. The spatial variation of the residence time is characterized by subdividing the Mondego Estuary into boxes. The observed average salinity for each box is applied to the freshwater fraction model. With the Lagrangian model, boxes are filled with tracers and the path of the particles passing through them is quantified. The overall results of the two methodologies are similar, with a value of the residence time varying over the year between 1 and 12 days computed with the Lagrangian transport model and 2 and 9 days with the freshwater fraction model. Several scenarios were built by applying the Lagrangian transport model to investigate the history of water renewal and the influence of freshwater inflows and geomorphologic factors on the residence time. The overall results indicate that freshwater inflow is the main factor influencing the residence time. The analysis of the history of the water renewal was carried out by calculating the water exchange among boxes inside the estuary, pointing to the river flow as the main factor contributing to the water renewal of boxes.

  19. Bedforms and Evolution of Tropical Estuaries: Examples from Northeastern Brazil

    NASA Astrophysics Data System (ADS)

    Vital, H.; Soares, C.; Rocha, G.; Pereira, T.; Eichler, P.

    2012-12-01

    This paper intends to show the geomorphological and sedimentary responses of tropical estuaries to meteorological and oceanographic forcing. The study area is located on the coastal zone of Rio Grande do Norte State, northeastern Brazil. This coast is under natural influence of waves and tides with a semidiurnal mesotidal regime and anthropogenic influence (urbanization, oil and salt industries, shrimp farms, and tourism). An operational methodology was developed using collection and analysis of an integrated dataset (comprising remote sensing, oceanographic, hy-droacoustic, and sedimentologic data). All data were integrated through a geographical infor-mation system database. The imaging of subaqueous features allowed the identification of differ-ent bedforms as well as submerged rocky outcrops. Four main groups of bedforms were identi-fied: 2D and 3D large dunes, ripples and flat bottom, and rocky outcrops as well. Rocky outcrops were correlated to Barreiras Formation and beachrocks. The estuarine channel is filled by Holocene sandy- to silt sediments, with sandy sediments in the main channel ranging from well-selected to selected grains, and silty sediments in the river margins. The integration and analysis of currents velocity and other physical parameters with bedforms characterization and different sedimentary textures in the study area allows a better knowledge of the active sedimentary processes, which are responsible for the formation of morphologic features of these estuaries. The evolution of estuary settings, led by the postglacial sea-level rise, is recorded in the subsurface an present-day riverbed. These results contribute to a better understanding of tropical estuaries.; Location of the study area

  20. Sensitivity of estuaries to sea level rise: Vulnerability indices

    NASA Astrophysics Data System (ADS)

    Prandle, David; Lane, Andrew

    2015-07-01

    This study addresses the question of how tidally-dominated estuaries will adapt to rises in mean sea level and changes in river flows associated with global climate change. The aim was to develop generic 'Vulnerability Indices' to provide immediate indications of relative resilience or sensitivity. Four indices indicate the likely impacts on: (1) Mass flow, (2) Energetics, (3) Vertical mixing and (4) Salinity intrusion.